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ORIGINAL ARTICLE
Taming the energy use of gaming computers
Nathaniel Mills &Evan Mills
Received: 11 December 2014 /Accepted: 8 June 2015 /Published online: 20 June 2015
#Springer Science+Business Media Dordrecht (outside the USA) 2015
Abstract One billion people around the world engage in
some form of digital gaming. Gaming is the most energy-
intensive use of personal computers, and the high-
performance Bracecar^systems built expressly for gam-
ing are the fastest growing type of gaming platform.
Large performance-normalized variations in nameplate
power ratings for gaming computer components available
on today’smarketindicatesignificantpotentialforenergy
savings: central processing units vary by 4.3-fold,
graphics processing units 5.8-fold, power supply units
1.3-fold, motherboards 5.0-fold, and random access
memory (RAM) 139.2-fold. Measured performance of
displays varies by 11.5-fold. However, underlying the
importance of empirical data, we find that measured peak
power requirements are considerably lower than name-
plate for most components tested, and by about 50 % for
complete systems. Based on actual measurements of five
gaming PCs with progressively more efficient component
configurations, we estimate the typical gaming computer
(including display) to use approximately 1400 kWh/year,
which is equivalent to the energy use of ten game con-
soles, six standard PCs, or three refrigerators. The more
intensive user segments could easily consume double this
central estimate. While gaming PCs represent only 2.5 %
of the global installed PC equipment base, our initial
scoping estimate suggests that gaming PCs consumed
75 TWh/year ($10 billion) of electricity globally in
2012 or approximately 20 % of total PC, notebook, and
console energy usage. Based on projected changes in the
installed base, we estimatethatconsumptionwillmore
than double by the year 2020 if the current rate of
equipment sales is unabated and efficiencies are not
improved. Although they will represent only 10 % of
the installed base of gaming platforms in 2020, relatively
high unit energy consumption and high hours of use will
result in gaming computers being responsible for 40 % of
gaming energy use. Savings of more than 75 % can be
achieved via premium efficiency components applied at
the time of manufacture or via retrofit, while improving
reliability and performance (nearly a doubling of perfor-
mance per unit of energy). This corresponds to a potential
savings of approximately 120 TWh/year or $18 billion/
year globally by 2020. A consumer decision-making
environment largely devoid of energy information and
incentives suggests a need for targeted energy efficiency
programs and policies in capturing these benefits.
Keywords Information technologies .Computing
energy use .Gaming computers
Context
In the quest for technological performance improvements,
the racecar is often invoked as a locus of innovation. In the
energy sector, this analogy has been applied to data cen-
ters as energy-intensive environments where significant
Energy Efficiency (2016) 9:321–338
DOI 10.1007/s12053-015-9371-1
N. Mills
http://GreeningTheBeast.org
E. Mills (*)
Lawrence Berkeley National Laboratory, Berkeley, USA
e-mail: emills@lbl.gov
innovations have been made in IT equipment as well as
the surrounding heating, cooling, and power-delivery in-
frastructure (Mills et al. 2007). Similarly, at the distributed
scales of personal computing, the high-performance gam-
ing computer (we subsequently refer to these by the
shorthand Bgaming computers^)(Fig.1)hasbeenthe
focus of efforts to boost performance in order to meet
rapidly increasing user expectations (Short 2013).
Estimates placed the flow of digital media to US
households at 6.9 zettabytes (ZB; 10
21
bytes) per
year in 2012, of which 2.5 ZB (34 %) was attributed
to gaming (Short 2013). US households are
projected to spend 211 billion hours of gaming in
2015, more than the time spent on the telephone,
mobile computing, or messaging. Use has doubled
since 2008. The 43.6 million Bextreme^and Bavid^
gamers spend 4.4 h/day in the activity (all platform
types) versus 7.2 h/day for the 10 million Bextreme^
gamer subgroup (Short 2013).
An estimated one billion people globally engage in
some form of personal computer gaming (PC Gaming
Alliance 2013). A small subset of people use their
computers exclusively for gaming, while most engage
in the typical array of computer activities. Even game
consoles have become general media devices. Game
consoles (e.g., PlayStation, Nintendo, and Xbox) have
received most of the attention within the energy com-
munity, often to the exclusion of far more energy inten-
sive gaming computers (Urban et al. 2014). There are
wide variations and strong trends in the choice of plat-
forms, with the installed base of game consoles
projected to decline and that of desktop gaming com-
puters to increase (Fig. 2).
The global count of people utilizing gaming com-
puters was estimated at 54 million in 2012 (33 countries
studied) and projected to grow to 72 million together
with sales of related computer hardware of $32 billion
by 2015 (Business Wire 2012). About half of the 100
million PCs with discrete graphical processing units
(GPUs) shipped in 2014 were purchased by consumers,
with the other half destined for workplace environments
(Peddie 2014).
Fig 1 A surround setup representing the epitome of desktop
gaming. A system such as this could approach 2000 W of name-
plate power, including displays and peripherals. Based on actual
measured demand, used 8 h/day in gaming mode, the system
would consume roughly 3500 kWh/year (perhaps $1400 with
aggressively tiered electric tariffs), comparable with a highly effi-
cient home. The underlying machine possesses two 500-WAMD
R9 295X2 graphics cards and a 1500-W power supply unit.
Sources: HardwareCanucks (2014)andhttps://twitter.com/
elmnator
Fig. 2 BEnthusiast^gaming
computers are a small but
growing segment of gaming
platforms (a rough proxy for the
aforementioned BExtreme^and
BAvid^user groups), with
consoles projected to decline.
This chart shows the installed
base (stock), with projections
from 2014. Excludes mobile
platforms (adapted from Open
Gaming Alliance 2015; Business
Wire 2012)
322 Energy Efficiency (2016) 9:321–338
Computer gaming is engaging an increasingly di-
verse user base. These consumers spent $22 billion on
gaming software in 2013 (ESA 2014), with the global
market estimated at $100 billion (Brightman 2013). The
scale and growth of this activity calls for assessment of
the associated energy use.
Just over half of all US households own a game
console, with the average player being 31 years old
and with males and females engaged in roughly equal
proportions. Previous studies exploring the energy im-
plications of game console use found average unit elec-
tricity use to be 102 kWh/year for the installed US stock
(excluding the connected display) and 64 kWh/year for
new sales as of mid-2012 (Webb et al. 2013).
1
There is
ongoing debate about game console utilization, with
recent studies finding that this may have been previous-
ly overstated (Desroches et al. 2015).
We found no prior studies focusing on the aggregate
energy used by gaming computers. One assessment
(Ecova 2012) examined the idle powerdemand of graph-
ic processing units embedded in gaming computers, and
another (Brocklehurst and Wood 2014)exploredwheth-
er these machines would be able to meet the ENERGY
STAR v6.0 requirements, based on pooling diverse test
results from third-party sources (not standardized for
factors such as choice of motherboard, duration of sleep
mode, overclocking, operating system, software running
during testing, etc.). Their results were confounded by
differences in test procedures.
This article provides new information based on
nameplate performance of gaming computers and their
components together with direct measurements. Effi-
ciency opportunities are identified. Using measured da-
ta, we produce the first global estimate of the associated
current and projected energy consumption and savings
potential.
Components, architecture, and eff iciency options
Gaming computers contain the same generic com-
ponents as conventional computers. However, the
performance requirements of these machines entail
far higher energy intensities, and in many cases,
multiple components (e.g., GPUs, hard drives, dis-
plays) are used. Protocols for benchmarking the
computational performance of gaming computers
involve running a preset gaming process and
collecting metrics. Some benchmarks focus on cen-
tral processor performance (e.g., Cinebench); others
focus on the graphics (e.g., Unigine Heaven; see
http://www.maxon.net/products/cinebench/overview.
html and https://unigine.com/products/heaven/).
Component product literature, however, emphasizes
nameplate estimates of power requirements, rather
than actual performance or power needs under a
given mode of operation. As discussed below,
accurate energy use calculations cannot be made
with nameplate data. However, no standardized test
procedures exist for evaluating gaming actual
computer energy use, which perpetuates market
reliance on over-estimates of nameplate data.
The limitations of nameplate data notwithstand-
ing, a review of the wide range of nameplate power
requirements for components of analogous perfor-
mance already on the market suggests that opportu-
nities exist for improved energy efficiencies in each
component, through hardware as well as control im-
provements (Table 1). A variety of metrics may be
defined for a given component. Useful metrics either
provide a direct efficiency measure or an analogous
ratio of energy or power inputs per unit of perfor-
mance provided. Here, we have picked metrics that
are either industry standards or otherwise readily
available in product technical specifications. Howev-
er, nameplate power ratings should not be used to
estimate energy use.
Motherboard
Most components are mounted on and orchestrated by
the motherboard, the main circuit board in the computer.
The motherboard also holds the chipset that manages
data flows among internal and external components.
Motherboard energy losses occur via voltage-
regulation modules (VRMs) as well as via natural resis-
tive losses depending on the thickness of traces used.
Increased voltage must be supplied via the motherboard
as CPU and random access memory (RAM) clock
speeds rise. As seen in Fig. 3, nameplate power
1
It is important to consider learning-curve effects. Console launch
models are typically two or more times as energy intensive than
the given model’s stabilized performance once several generations
of design refinements have been made (Delforge and Horowitz
2014); for example, the 2006 release version of PlayStation 3
required 180 W in Bgame play^mode, which ultimately stabilized
at 70 W in the 2013 version.
Energy Efficiency (2016) 9:321–338 323
Tabl e 1 Components of gaming computers and efficiency opportunities
Nameplate/rated power
a
Efficiency range
a
Energy saving strategies
Motherboard 30 to 150 W 13–65 W/GHz of max
supported CPU
More efficient capacitors; improved power delivery
efficiency and control. Some motherboards allow the
user to disable components not in use (e.g., HDMI,
PCI-E slots, or SATA ports).
Central processing
unit (CPU)
architecture
37 to 220 W 15–63 W/GHz Decreased size and increased transistors per unit area
(less leakage). Power scaling (e.g., Intel Sandy
Bridge (85 W) vs. Ivy Bridge (77 W) vs. Haswell
(65 W) illustrate the generational progression). C-state
(aka BC-mode^) capabilities enable CPU to vary
power draw as a function of workload, with particular
emphasis on increasingly sophisticated sleep modes.
There are currently 13 C-state gradations, some of
which can be changed by the user in the Basic Input/
Output System (BIOS). Selected voltages can be
reduced within the CPU without reducing
performance (but with reduced stability CPUs can
be underclocked to reduce power consumption
(but with reduced performance). Multiple cores may
or may not affect efficiencies, depending on
computational activity and software.
Graphical processing
unit (GPU)
75 to 500 W 32–187 W/TeraFLOP Decreased size and increased transistors per unit area
(less leakage). Power scaling (e.g., NVIDIA
Fermi vs. Kepler vs. Maxwell). GPUs can be
underclocked for additional energy savings (but
with lower performance). Modes exist for disabling
GPUs when the display is off. Displays with
Banti-tearing^features enable use of lower-power
GPUs.
Fans Low single-digit watts, but
can be many fans (typically
5–6) in a single computer
W/CFM Efficiency of air movement. Automated power-down
at low loads. Improved blade designs. Reduced fan
count commensurate with efficiency improvements
elsewhere in the system.
Memory DDR (2.5 V)≥DDR2 1.8 V) ≥
DDR3 (1.5–1.65 V)≥DDR4
(1.2–1.35 V)
13–65 W/GHz Reduced voltages. Fewer higher-capacity modules
(Bsticks^).
Storage HD (~10 WW)≥SATA SSD
(~5 W)≥PCI-E SSD (~3 W)
44–139 W/GHz Switch from mechanical to solid state with
significant performance boost in reads and writes.
Power supply unit
(PSU)
Intrinsic energy use only from
dedicated fans. Indirectly
associated with losses due
to power conversions for
downstream loads.
70 % efficiency≥80 %
(80Plus threshold)≥94 %
(80Plus Titanium; all at
50 % load)
Efficiency; some units are fan-less, saving several
watts; others curtail fan use until high power
thresholds are reached. Sizing to match load is
important for peak efficiency, although less so as
the industry has attained more consistent efficiencies
across the load range.
Displays 15 to 77 W (23–34 in.
size range)
4.8–41 W/megapixel Technology choice (CRT vs. LCD/LED, +backlighting
strategy, as well as techniques to avoid image
tearing with lower GPU speeds. Power management
(e.g., sleep mode), dynamic dimming as a function
of room light levels, and occupancy-sensor-initiated
sleep mode. Improving transmissivity of film stack
to improve luminous efficacy. Display-specific
PSUs also present efficiency opportunities.
Operating system Various energy management tools are available via
the OS.
Voltage levels Tuning voltages to required performance level.
Constant voltage vs. ASUS EPU engine.
Power down Curtailing operation of some or all components after
designated time. Monitor sleep functionality; GPU
staged control where unit has multiple processors
324 Energy Efficiency (2016) 9:321–338
consumption varies between 30 and 150 W across a
sampling of devices found in the market today.
Central processing unit
The central processing unit (CPU) conducts the pri-
mary computing tasks and is one of the important
nodes of energy use. Steady progress has been made
in the energy efficiency of CPU architecture. One
metric of efficiency is the ratio of peak power re-
quirement to corresponding processor speed. As
seen in Fig. 4, nameplate power consumption varies
between 37 and 220 W across a sampling of devices
found in the market today. The service levels pro-
vided by these devices vary as well, as reflected in
their differing clock speeds (measured in gigahertz).
CPUs can be Boverclocked^to above the rated per-
formance levels indicated here, increasing power
consumption.
Graphics processing unit
The graphics processing unit (GPU) provides comput-
ing power associated with visual display of information,
including two- (2D) and three-dimensional (3D) render-
ing and animations and is typically the single-most
important node of energy use. Gaming computers rely
heavily on discrete GPUs, which are typically more
power-intensive than CPUs. Steady progress has been
made in the energy efficiency of the GPU architecture.
This is driven by the imperative to control heat produc-
tion, as opposed to saving energy per se. One metric of
efficiency is the ratio of peak power requirement to
corresponding floating-point operations per second
(FLOPS). As seen in Fig. 5,nameplatepowerconsump-
tion varies between 60 and 500 W across a sampling of
gaming-specific devices found in the market today. The
performance levels provided by these devices vary as
well, and they can be overclocked (to frequencies above
stock settings).
Tabl e 1 (continued)
Nameplate/rated power
a
Efficiency range
a
Energy saving strategies
(e.g., AMD Bzero-core^technology) or
thermostatically controlled fans.
Intelligent automatic
fan control
Variable speed control as function of eight internal
temperature sensor signals. Some GPUs allow user
to specify desired fan speeds as a function of
temperature. T-Balancer: Big NG.
a
Ranges apply to units included in the Figs. 3,4,5,6,7,and8, and generally reflect conditions at peak loads
Fig. 3 Performance-power
relationships for nine
motherboards suitable for use in
gaming PCs in the marketplace as
of December 2014. Performance
of the products shown here varies
considerably, from about 13 to
65 W/GHz, representing a
variation of 5-fold
Energy Efficiency (2016) 9:321–338 325
Memory and storage
RAM holds data until called by the CPU. The underly-
ing technology is solid state. Each Bstick^(DIMM) of
memory experiences losses, and there are typically mul-
tiple sticks per machine. Efficiencies have improved
dramatically over time. The current range is represented
by the spectrum of the double data rate (DDR) standard
(2.5 V, 17.5 W) to DDR4 (1.2 V, 1.3 W) (Fig. 6). There
are two general categories of storage devices, mechan-
ical (rotating) and solid state. The more poorly
performing mechanical hard drives draw on the order
of 10 W (1 TB) while solid-state drives of the same
capacity and interface draw as little as 2.6 W.
Operational savings occur depending on whether or
not a sleep mode is employed.
Cooling
Gaming computers require dedicated cooling systems in
order to avoid overheating, even at idle. Active cooling is
typically provided to each power supply unit (PSU),
CPU, GPU, and motherboard as well as to the general
environment within the computer chassis. In a CPU air
cooler, there are typically one to three fans driving hot
exhaust air across a heat sink. With liquid cooling, a heat
exchanger mounts to a particular component (CPU,
GPU, motherboard, or memory) and directs the coolant
Fig. 4 Performance-power relationships for 23 CPUs suitable for
use in gaming PCs in the marketplace as of December 2014.
Metrics are based on Bboost clock speeds^from manufacturer spec
sheets. There are no universally appropriate metrics for CPUs, as
performance varies based on many contextual factors as well as the
degree of parallel versus linear processes that are running for a
given task, and the degree to which a given application allows
multi-threading. The performance-normalized energy efficiency of
CPUs shown here varies considerably, from about 15 to 63 W/GHz
based on rated clock speed, representing a variation of 4.3-fold
(without overclocking)
Fig. 5 Performance-power
relationships for 27 GPUs
suitable for use in gaming PCs in
the marketplace as of December
2014. Metrics are based on
manufacturer-reported Bboost
clock speeds^from manufacturer
spec sheets. The performance-
normalized energy efficiency of
the GPUs shown here varies
considerably, from about 32.3 to
186.6 W/TeraFLOP, representing
a variation of 5.8-fold (without
overclocking)
326 Energy Efficiency (2016) 9:321–338
over a heat-exchange plate that is in direct contact with
the component. Liquid cooling is often preferred because
it allows the processor to achieve higher overclocks
(enhancing computational performance at lower temper-
atures). We measured CPUs with and without liquid
cooling, and no change in energy use was observed.
Power supply units
All power delivered to the gaming computer’sinternal
components passes through a power supply. Because
power supplies are upstream from the other components
and have intrinsic inefficiencies due to AC-DC power
conversions, the losses (and associated unwanted heat
gains) can be very significant, usually second only to the
energy used by the GPU. The efficiencies of PSUs
located within the PC typically peak around 50 % load.
Power supplies formerly had particularly poor efficien-
cies at part load, below 70 %. Significant improvements
occurred after the introduction of the voluntary B80Plus^
testing and rating program in 2004. As seen in Fig. 7,
efficiencies vary among a sampling of devices found in
the market today, from 69 to 94 % depending on the
project and degree to which it is loaded. Right-sizing
power supplies are thus important for optimizing oper-
ating efficiency. Most PSUs have dedicated fans for
cooling, which typically always run, although some
have temperature-controlled cooling.
Displays
While typically not hardwired to the gaming computer
itself, with the exception of notebooks and consoles,
displays are integral and energy-intensive elements of
the system. Moreover, although independently powered,
display choice influences power requirements and per-
formance of the GPU in gaming mode. Energy use varies
widely as a function of technology, screen size, and
resolution. The dramatic technology transitions that have
occurred in displays, resulting in significant energy
Fig. 6 Performance-power
relationships for four generations
of 1-DIMM 8 GB DDR memory.
Performance (W/GHz) varies by a
factor of 139. From left to right:
DDR4, DDR3, DDR2, and DDR.
DDR and DDR2 are early
generations, no longer in use.
DDR3 was introduced in 2008.
DDR4 was introduced in late
2014. Some versions of server
DDR3 approach the efficiency of
DDR4 (Koomey 2012)
Fig. 7 PSU efficiencies vary by
load, particularly among lower-
efficiency models. Each curve
represents one of nine devices in
the marketplace as of 2014.
Values do not include dedicated
fan energy. Actual losses depend
on weighted-average load over
the utilization period. Note that
80Plus requires efficiencies over
80 % at all loads, and the current
(USEPA 2013) requirements are
82, 85, and 82 % at 20, 50, and
100 % load, respectively
Energy Efficiency (2016) 9:321–338 327
benefits, have been driven more by the desirable form
factors and image quality than by energy savings.
Countervailing trends are the transition from VGA/
SVGA to HD/1080p, to 4 K displays, as well as the use
of multiple displays. The net effect is that GPUs must
drive many more pixels than was the case just a decade
ago.
Gamers have historically been irked by visual anom-
alies such as image Btearing^and Bstuttering^.Tearing
occurs when a frame is outputted by the GPU when the
monitor is in the middle of a refresh. One solution to this
issue involves enabling V-Sync (Vertical Sync) where
tearing is eliminated by forcing the GPU to wait until
the monitor is ready to refresh the next frame. This can
cause unacceptable delays in screen refreshes, i.e.,
stuttering. New technologies such as G-sync (NVIDIA,
hardware) and FreeSync (AMD, software) allow more
effective communication between the GPU and the mon-
itor. When these run during gameplay, the GPU tells the
monitor when to refresh, resulting in little to no stuttering
and no tearing. If the frame-rate in the game is low, these
approaches will synchronize the GPU output with the
game’scapacitytorender.Thissavesenergysince,even
at around 30 to 50 frames per second (FPS), the gaming
experience becomes smoother to the gamer’seye,en-
abling the gamer to specify a GPU with lower nominal
performance (and power requirements). With these tech-
nologies, manufacturers claim that gaming will be as
smooth as with a higher-power GPU.
One metric of display energy performance is the ratio
of the peak power requirement (in on mode) to corre-
sponding pixel count. As seen in Fig. 8,measuredpower
consumption varies between 15 and 77 W across a
sampling of displays found in the market today, with
wide variations on power consumption even within the
constraints of a given display size and resolution.
Nameplate power estimates and energy use
of gaming computers
The capabilities and performance of gaming computers
vary widely, depending on which components are se-
lected. Components with similar computing perfor-
mance must be compared in order to evaluate baseline
energy use and savings potential in a meaningful way.
While many other consumer products (including game
consoles) are typically evaluatedin terms of total system
load, gaming computers can also be evaluated at the
component level. However, it must be kept in mind that
nameplate power values are often far higher than max-
imum power use.
We identified commercially available components
that would be used to build three gaming computers
with similar performance but with progressively lower
power requirements. As seen in Figs. 9and 10,name-
plate power estimates vary substantially for the individ-
ual components and for the systems as a whole.
Fig. 8 Performance-power relationships for 37 displays in the 23-
to 34-in. size range suitable for use with gaming PCs in the
marketplace as of December 2014 (measured values, based on
the ENERGY STAR test procedure in active mode). The displays
chosen are those within the category favored by gamers (high
refresh rates) and reflected the overall variance seen among the
superset of displays meeting those criteria. The performance-
normalized energy efficiency of the displays shown here ranges
from 3.6 to 41 W/megapixel, representing a variation of 11.5-fold
328 Energy Efficiency (2016) 9:321–338
Brocklehurst and Wood (2014) similarly found that
efficiency and performance were not correlated.
The resulting scenarios for high-power, typical-
power, and low-power configurations nominally
draw 923, 601, and 331 W, respectively (including
displays). Note that in many warm locations, or in
many large commercial buildings, significant addi-
tional electricity use would be required for air con-
ditioning (not accounted for here) needed to remove
the heat produced by these machines. In other loca-
tions the computer’swasteheatmaybeusefulfor
part of the year.
Individual gaming computers could have higher
power consumption than these reference machines.
This can arise not only where less efficient compo-
nents are used but also where multiple monitors,
GPUs, or storage devices are employed. Additional
discretionary energy-using components (internal or
external) include sound cards, digital-analog con-
verters (DACs), headphones, amplifiers, speakers, net-
working equipment, RAID cards, powered keyboards,
pointing devices, and decorative lighting. The most
energy-intensive component in the gaming computer
is the graphics processing unit (GPU), and 1.4
graphics cards were sold for each computer sold in
2014 (JPR 2014)
2
; only one GPU is assumed in these
reference machines. Overclocking also increases power
consumption and waste heat, as does disabling power
management features.
Applying our methodology we estimated nameplate
power for the BTop- 10^gaming computers as ranked by
PC Magazine for the year 2014 (Fig. 11). We found that
the top-rated computer also had the highest nameplate
power. It was also the highest performing machine. The
ranking, however, would be quite different were the set
of machines ranked by relative power draw per unit of
performance.
While on the one hand, the above-referenced market
data suggest exceptionally high energy use, it is also
important to observe the large variation in the various
intensity metrics. The history of computing has shown
sustained and significant strides in intrinsic energy effi-
ciency (e.g., calculations per second per watt) and that is
2
This industry-wide statistic includes all types of desktop com-
puters, while virtually all machines incorporating multiple
graphics cards are gaming PCs (which are a small segment of
the overall market). Thus, this value is likely a conservative
reflection of the actual practice. Having multiple graphics cards
is a very widespread practice among gamers, and some machines
are even shipped from the factory with two installed.
Fig. 9 Differences in nameplate/rated power levels result in differ-
ences in annual electricity use. The components have comparable
performance levels in games: One CPU (Intel Core i7 4960X
3.6 GHz, Intel Core i7 4770 K 3.5 GHz, and Intel Pentium G3258
3.2 GHz); One GPU (AMD Radeon HD 7970 GHz Edition, NVID
IA Geforce GTX 780, and NVIDIA Geforce GTX 970, with
corresponding TeraFLOP benchmarks of 3.8, 4, and 4,
respectively); displays—all 27 in. and 3.7 MP (Apple Thunderbolt,
ASUS PA279Q, and ASUS PG278Q). No refresh-rate overclocking
assumed. Power supply draw is computed by multiplying the sum of
component power by one minus PSU efficiency at 50 % load.
Excludes space-conditioning energy impacts outside the computer.
Assumes one display
Energy Efficiency (2016) 9:321–338 329
evident in the gaming PC arena where efficiencies double
every 18 months (Koomey et al. 2011). That said, con-
sumer demand for increased performance has risen even
more quickly, with the net effect of rising absolute energy
use. These points notwithstanding, given the limitations
of nameplate information it is important to explore the
actual outcomes by examining measured data.
Measured power and energy benchmarks
Extending nameplate power to estimates of actual ener-
gy use is not straightforward. The resultant energy use
depends on differences between actual and nameplate
capacity as well as the mix of usage modes and duration
of use in each mode (e.g., off, sleep, idle, active gaming,
video/movie playback, and Web browsing). For exam-
ple, Webb et al. (2013) found that approximately half of
the on-time for game consoles is in Bgameplay^mode.
Each game or process (e.g., 3D rendering) has its own
energy intensity. Moreover, there are a variety of levels
of computing demand even within the general activity of
Bgaming,^and energy use is also software specific.
Little measured data has been collected for gaming
PCs and their sub-components. The performance of a
given component relative to that of other components in
Fig. 10 This particular selection
of low-power components results
in a system that nominally draws
66 % less power than the highest-
wattage choices available. These
values reflect nameplate operation
(same systems as described in
Fig. 9); in-use, components often
have substantially lower power
demand. Assumes one display.
Excludes associated space-
conditioning energy impacts
outside the computer
Fig. 11 PC Magazine ranks the (highest energy-using) machine in
first position (left). Unigine Valley performance benchmarks range
from 42 frames per second (FPS) to 302 FPS (middle).
Benchmarked nameplate watts per FPS, as a proxy for efficiency,
varies by a factor of 30 (right). Excludes associated space-
conditioning energy outside the computer (Ragaza 2013)
330 Energy Efficiency (2016) 9:321–338
the system will also vary significantly depending on the
mode of operation. In one example, a particular mother-
board ranked average compared with 11 others (using
identical CPU) when in long-idle mode, above average
in idle mode, and lower than average in active computing
mode (Cutress 2014).
We constructed a baseline gaming computer using
popular components on the US marketplace as of
December 2014. We then measured power requirements
and energy use by mode while running common gaming
performance benchmark software. Our test-bench
machine contains a motherboard that utilizes the X79
(aka Patsburg) chipset and an LGA 2011 CPU, noted by
others (Brocklehurst and Wood 2014) to be among one
of the highest performance Intel platforms on the
market. (As of August 2014, X79 was succeeded by
the X99 (Wellsburg) chipset and LGA 2011–3Socket).
We performed a range of system-level measurements
in different modes of operation, capturing loads from
Boff^to full gaming mode status. We adopted estimates
by Short (2013) for average times spent by US gaming
computer users in various modes of operation. We in-
cluded short idle times (measurements over the interval
of 5 to 10 min after cessation of user inputs) as well as
long idle times (after idle for 10 min of idle) per the
ENERGY STAR v6.0 test procedure and no B2D^
operation (only benchmarking software was running
during tests) (USEPA 2013). Established software per-
formance benchmarking tools were utilized to stress test
the components and create replicable results under con-
ditions used more broadly in the industry. One-second
power data were taken with Watts-Up Pro ES data
logger. Internal and after-market software enabled sub-
metering in some cases (PSUs, CPUs, and GPUs).
Measured power consumption and energy use for our
base case varied significantly as a function of usage
mode. Measured peak electricity demand in active gam-
ing mode at 512 W is six times that of a typical desktop
computer and its associated display and three times that
in idle mode (Urban et al. 2014). The mode-weighted-
average power draw during on-time was 212 W.
Operational settings have significant impact on ener-
gy use as well as temperatures. In keeping with the
Bracecar^analogy used earlier, overclocking CPUs is a
popular practice among gamers as a means for boosting
computing performance. We evaluated our base CPU at
rated and overclocked settings and found significant
energy impacts. Elevating clock speed from 3.7 to
4.5 GHz increased peak power requirements during the
Cinebench CPU test from 167 to 217 W (23 %). Perfor-
mance (benchmark scores) increased by 16 %, indicating
that energy efficiency declined by 9 %. Note, per Table 2,
that half of this effect is upstream of the CPU itself
(power supply losses, power delivery to CPU, chipset
work, etc.) and that the CPU draws far less power than its
nameplate rating, even when overclocked. Some opera-
tional strategies seem to have relatively little effect.
We do cument di ff er en ces in name pl at e and measu re d
power values in Table 2.Thiseffectiscompoundedwhere
multiple components are evaluated when assembled as a
system, with a 49 % disparity during gaming mode in the
case of our built-up system. One important ramification of
Tabl e 2 Disparities between nameplate and actual component power requirements
Nameplate rating (W) Measured power (W, at peak) Difference (%)
CPU: Intel Core i7 4820 K (at 3.7 GHz, rated)
a
130 70 −46
CPU: Intel Core i7 4820 K (at 4.5 GHz, overclocked)
a
130 79 −39
CPU: Intel Pentium G3258 (at 3.2 GHz, rated)
a
54 27 −50
CPU: Intel Pentium G3258 (at 4.0 GHz, overclocked)
a
54 43 −20
GPU: NVIDIA Geforce GTX 970 (at 1102 MHz, rated)
b
145 145 0
Apple HD Cinema Display 90 75 −17
Apple Thunderbolt Display 165 106 −36
ASUS VG248QE 45 18 −60
Full-base system benchmark: CPU test
a
560 201 −64
Full-base system benchmark: gaming mode
c
810 414 −49
a
Measured value based on peak wattage using Intel Power Gadget over Cinebench CPU benchmark stress test
b
Value measured with OC+ module, found on Zotac GTX900-series amp Omega and Extreme edition graphics cards
c
Measured value based peak wattage over the Unigine Heaven gaming benchmark test
Energy Efficiency (2016) 9:321–338 331
these disparities is the degree to which PSUs will likely be
oversized if nameplate performance is relied upon.
Based on our measurements, Fig. 12 illustrates power
and energy use as a function of time and mode for what we
deem to be a Btypical^vintage 2014 gaming computer over
a24-hdutycycle.Whilethisinitialscopingestimateis
based on measurements of discrete assemblies, the compo-
nents selected are representative of market tendencies and
the weighted average attach rate of 1.4 GPUs/computer.
The assumed time in each mode of operation represents
population-level utilization rates for US conditions.
The results indicate unit energy consumption of
1394 kWh/year (based on an average of 4.4 h/day in
gaming mode), including the display. The BAvid^user
sub-segment (29.5 million people, USA) spends 3.6 h/day
gaming, uses 1300 kWh/year, while the BExtreme^user
segment (8.1 million people) spends 7.2 h/day uses
1890 kWh/year (36 % more; utilization rates from Short
2013). For the typical gamer (4.4 h/day, weighted average
of Avid and Extreme), we found that a much larger
proportion of total energy (80 %) occurs in modes above
idle than is the case for traditional personal computers,
which have low computing loads (Beck et al. 2012).
High-performance computers in work environments (not
included in this analysis) will also have high consumption
where there are more average daily hours of use.
Fig. 12 Measured power and energy use for each mode of oper-
ation. The active gaming value is an average observed during the
benchmark trials described below, with adjustments to reflect an
80 % efficient PSU and 1.4 GPUs (average in use). Components:
PSU (Seasonic G Series, 550 W), CPU (Intel Core i7
4820 K—quad core, 3.7 base GHz), GPU (NVIDIA Reference
Geforce GTX 780, 900 MHz boost), motherboard (ASUS P9X79-
EWS),RAM(32GB(8×4GB)KingstonHyperXBeast
1866 MHz, 1.65 V), display (Apple HD Cinema, 23 in.). Operat-
ing system: Windows 7 Professional 64 bit; BPower saver^energy
management settings in Windows 7 OS. Operating hours: active
gaming (Open Gaming Alliance 2015), Web browsing and video
streaming (Short 2013), idle from Urban et al. (2014), and off/
sleep is residual divided equally. Assumes one display
Fig. 13 System power
consumption throughout the
10-min Unigine Heaven gaming
benchmark. A 25 % reduction in
energy use between the two GPUs
is achieved. Excludes display.
Note: brief drops are transitions
between 3D-rendered scenes
332 Energy Efficiency (2016) 9:321–338
The cost of this electricity would be on the order of
$200/year at typical household electricity prices (and
easily $500/year where tariffs are usage dependent,
e.g., with an inverted-block design). This, in turn, cor-
responds to emissions of approximately 1700 lbs
(780 kg) of carbon dioxide/year at US-average electric-
ity emissions factors (USEPA 2010).
These estimates are likely conservative, as we as-
sume only one display per user, no peripherals such as
audio equipment, and no overclocking of CPUs or
GPUs, and BPower saver^settings in the operating
system.
Energy efficiency potential
To explore the potential for efficiency improvements
and corresponding energy savings, we made a series of
progressive hardware improvements to the system and
measured the response. These included a more efficient
PSU, GPU, CPU, motherboard, and display.
Each of these improvements had a significant effect
on measured energy use. For example, we installed and
evaluated two graphics cards under the Unigine Heaven
benchmark test (Fig. 13). Peak demand was 19 % lower
with the more efficient GPU, and 25 % energy savings
was achieved across the test cycle (excluding display).
Energy use for the system was reduced by 13 % across
all modes of operation, with no reduction in GPU com-
puting performance. Many examples of the lack of
performance-energy relationship can be observed in
Figs. 3,4,5,6,7,and8.
As shown in Fig. 14,totalenergyuseforthe
collection of upgrades was reduced by almost
50 %. Gaming performance remained essentially
unchanged with Unigine Heaven FPS benchmarks
and declined for CPU tasks because the new CPU
had fewer cores. A system-level gaming-mode
Fig. 14 The Base system is described in Fig. 12, although here we
have only 1 GPU. The energy efficiency improvements, from left
to right, were progressively upgraded to a 92 % efficient PSU
(Corsair AX760), improved GPU (Zotac Geforce GTX 970 AMP!
Omega edition), improved motherboard (ASUS Sabertooth Z97
Mark I) and CPU (Intel Pentium G3258), and improved display
(ASUS VG248QE modified with NVIDIA G-sync). Gaming
performance remained essentially unchanged, resulting nearly a
doubling of system energy efficiency
Energy Efficiency (2016) 9:321–338 333
efficiency metric defined as peak FPS/annual elec-
tricity use nearly doubled.
We find that each gaming computer is a significant
energy user. For context, the average energy use of our
Btypical^machine is equivalent to that of ten game
consoles, six conventional personal computers, and
three ENERGY STAR refrigerators (Fig. 15). The effi-
cient case corresponds to the most efficient configura-
tion depicted in Fig. 15.
Additional savings can be achieved through opera-
tional settings. One analysis based on adjustments to the
CPU and motherboard achieved 27 % savings in stand-
by power, and 26 to 30 % savings in active mode
(3DMark and Cinebench benchmarks, respectively)
without a reduction in performance (Crijns 2014). Ad-
ditional adjustments involving underclocking and volt-
age management yielded 44 and 64 % allowing for 16
and 30 % reductions in performance under the same
benchmarks. Combined with the efficiency gains
achievable with improved CPU, GPU, and mother-
boards can thus be expected to yield a total of more than
75 % annual energy savings.
Some efficiency improvements have ancillary bene-
fits. For example, the base GPU in our comparison
experienced internal temperatures of 91 °C during the
Unigine Heaven benchmark trial, which fell to 65 °C
with the more efficient unit due to improved cooling,
power delivery, and power consumption. This supports
increased reliability and service life, while reducing fan
speeds and noise and achieving lower temperature en-
vironments for nearby components.
Role of consumer information environment,
decision-making and behavior
Gaming computer purchasers face many barriers to
making energy-efficient choices. Most components bear
no energy-related information on their packaging or
when bought on-line without packaging. This includes
the most energy-intensive components (graphics cards
and CPUs), which do not even carry nameplate power
estimates on their packaging or on the product itself.
Even spec sheetsdo not always contain this information.
Integrated systems also typically lack information on
requirements, aside from the nameplate power of typi-
cally oversized PSUs.
Thus far, no labeling programs differentiate the ener-
gy performance of gaming computers. The highest long-
and short-idle power requirement among ENERGY
STAR-rated desktop computers are 33 and 63 W, re-
spectively, which suggests that no gaming computers
have received ENERGY STAR ratings. At least in the
USA, mandatory energy efficiency standards do not
exist for any components found in gaming computers.
Retail salespeople are poorly equipped to coach
buyers. Some that we interviewed use highly imprecise
rules of thumb when recommending power supplies,
e.g., based on unreliable nameplate performance of the
associated graphics card plus a Bsafety margin.^It is
encouraging that some industry watchers have proposed
that metrics be developed to consider total cost of own-
ership (including energy costs) (Pollak 2010), but this
has yet to become mainstream thinking.
Power supplies have received more attention over the
past decade than other gaming computer components,
leading to the voluntary 80Plus program (Calwell and
Ostendorp 2005). The program includes a staged rating
Fig. 15 The average new console uses approximately 134 kWh/
year (including the console unit at 62 kWh device as per Webb
et al. 2013 connected to an average television with energy use per
Urban et al. 2014, with 2.2 h/day utilization as per Short 2013),
and the average personal computer 246 kWh/year (Urban et al.
2014). All values include external displays. Values for average
refrigerators from www.energystar.gov.Valuesforgaming
computers are from this study
334 Energy Efficiency (2016) 9:321–338
system denoted by bronze, gold, platinum, and titanium.
In retail environments, we observed misleading product
labeling, where words like Bgold^and Bsilver^were
used in a way that masks the absence of an actual 80Plus
rating.
Aside from 80Plus, energy test procedures are not
standardized, creating considerable confusion in the
consumer information environment. For example, three
Websites rate an identical motherboard at 62, 92, and
98 W (a 58 % difference across the range)—all at idle
and independent of associated CPU (see http://www.
guru3d.com/articles_pages/asus_z97_sabertooth_
mark_1_motherboard_review,8.html;http://www.
kitguru.net/components/motherboard/luke-hill/asus-
sabertooth-z97-mark-1-motherboard-review/12/;http://
www.tweaktown.com/reviews/6345/asus-sabertooth-
z97-mark-1-intel-z97-motherboard-review/index8.
html). Such differences could arise from a range of
factors not typically standardized (or even disclosed)
in test reports. Examples include disparate power
supplies or power management. Standardized test
procedures are clearly needed.
Technical efficiency ratings reach only so far, as user
behavior is an over-riding factor in ultimate energy use.
As noted previously, hours of use vary widely, as do
consumer desires regarding extreme performance capa-
bilities, display count and area, peripherals, etc. The
sports-car analogy applies here in that technical energy
savings are easily Btaken back^in return for increased
performance and corresponding energy use.
The net Bworst-case^effect of consumer-determined
factors is the high-power multi-display system depicted
Fig. 16 Energy use estimates are the product of the number and
type of platforms (Fig. 2) and unit energy consumption based on
measurements, assumed constant at current levels: gaming com-
puters used by Benthusiasts^(this article); other devices are defined
in caption to Fig. 15.Thefractionofenergyusefornon-gaming
purposes is higher for mainstream and casual users than for the
dedicated enthusiast platforms—average enthusiast use is 4.4 h/day;
average mainstream and casual use is about 1.5 h/day (Short 2013).
Values include computer, display, and network equipment. The
proportion of energy used expressly for gaming on conventional
(Bcasual^)PCshasnotbeenisolated.Excludesmobileplatforms.
Based on projections of installed base from 2015 forward per Open
Gaming Alliance (2015)
Tabl e 3 Global gaming computer energy use in context: 2012
Desktop
PCs
a
Notebooks Tablets Game
consoles
Gaming PCs:
pre-built
a
Gaming PCs:
user assembled
All devices Gaming PCs as
fraction of total (%)
Unit energy consumption
(kWh/year)
b
246 53 6 155 1394 1394
Installed base in 2012
(million units)
801 882 184 250 36 18 2170 2.5
Tot al ener gy c onsum ption
in 2012 (TWh/year)
197 47 1 39 50 25 359 21
a
Gaming pre-built base deducted from estimate provided by this source and reported in own column to the right
b
Unit energy consumption follows Fig. 15. Installed base: conventional PCs from statista.com; Tablets Forrester Research (2013); consoles
and gaming PCs: stock from Open Gaming Alliance (2015)
Energy Efficiency (2016) 9:321–338 335
in Fig. 1. For perspective, that system entails three-times
the nameplate power of our Btypical-power^case and
seven times that of the Blow-power^case shown in
Figs. 9and 10.
Global energy use
Using the available data, we made an initial scoping
estimate of global energy use by desktop gaming com-
puters, and placed it in context with that of other devices
used for gaming (Fig. 16, Table 3). Gaming computers
are the fastest growing segment and have the highest
unit energy consumption. This estimate should be con-
sidered approximate, pending further research to mea-
sure a larger number of actual gaming computers.
We find that, although they represent only 7 % of PC,
notebook, and console gaming platforms, gaming com-
puters were responsible for electricity use of 75 TWh/
year in 2012 (or approximately $10 billion/year) equal
to 30 % of all energy use across this array of devices.
Placed in a broader context, this represents about 20 %
of electricity used by all PCs, notebooks, consoles, and
tablets (Table 3).
As noted previously, users with multiple displays,
multiple graphic cards, or other discretionary compo-
nents will require even more energy. Additional energy
will also be used in association with air conditioning in
hot climates. Trends in technology and behavior (hours
of use, by mode) may prove to be as important determi-
nants of energy demand as changes in the hardware
itself. Prior macro-level studies have not isolated the
energy use by these machines from that of conventional
computers.
The potential to reduce energy demand from gaming
computers by more than 75 % is enhanced by the very
rapid turnover of equipment (several years at the most),
the ability for individuals to specify high-efficiency
components (new or retrofit), and the significant
co-benefits of energy efficiency enhancements for
equipment performance, thermal management, and
reliability. One of the more pronounced historical
examples of technological process is the simulta-
neous 10-fold improvement in speed of RAM, ac-
companied by a 13-fold reduction in power require-
ments (Fig. 6). A key illustration of current oppor-
tunities are fan-less PSUs, which not only save
significant energy due to the high efficiency asso-
ciated with eliminating the need for cooling but
also trim approximately four constant watts of base
load demand, while attaining reduced noise and
increased reliability by eliminating the dedicated
fan altogether.
Conclusions
There is a wide range of energy use among individual
gaming computer components as well as integrated
systems. The metrics we computed suggest a corre-
spondingly wide range in efficiencies, i.e., energy use
for a given level of computing performance. This dem-
onstrates that high performance can be attained without
compromising efficiency. The energy use of gaming
computers is significant, and growing, and projected to
more than double by 2020 assuming today’sefficiencies
and current projections of an increasing installed base of
equipment. Overall efficiency improvements of 75 % or
more are attainable, which would translate to savings of
approximately 120 TWh/year or $18 billion/year at a
global scale in the year 2020. Assumptions underlying
the typical computer modeled here likely understate
energy use in practice.
The results of prior studies have been confounded by
uncertainties introduced by relying on nameplate rather
than measured data, as well as disparate test conditions
and test procedures. We find that nameplate power
estimates for the key components in gaming computers
significantly exceed power use in practice (on the order
of 50 %) and their direct use can thus yield overesti-
mates of energy use. This problem requires attention
through further testing under as-used conditions and
applied towards improved consumer information and
ratings. The energy requirements of specific gaming
applications can also be evaluated.
From a technological standpoint, component effi-
ciencies will no doubt continue to improve. Advanced
control strategies are also important. Unlike almost all
other energy-using products (including commodity
PCs), a large share (one third) of gaming computers
are specified and assembled by end users. This opens
up a unique opportunity for interested consumers to
attain efficiencies otherwise unavailable on the market.
There is a promising trend towards more efficient
notebook-format gaming computers. This has historical-
ly been difficult given the relatively large physical di-
mensions and weight of high-performance components
and severe challenges in thermal management and
336 Energy Efficiency (2016) 9:321–338
battery life within the small form factor of notebook
computers. Gaming notebooks, however, do not com-
monly deliver the same computing performance as do
desktops but are improving.
Our macro-level results are certainly preliminary in
nature, and suggest that the issue calls for much more
rigorous analysis, which, in turn, requires the collection
of more market data. In the future, finer-grain data on
equipment stocks, energy using characteristics, and user
behavior will allow for more precise and disaggregated
energy-use estimates (e.g., in homes versus workplaces,
the latter of which is not incorporated in our analysis).
The additional gaming-related energy use of general-
purpose computing devices also remains to be estimat-
ed. To enable improved energy analyses as well as better
consumer decision making, standardized methodologies
should be developed to more rigorously and consistently
benchmark and normalize energy use and peak power
demand of computers as well as that for specific games.
The mainstream gaming computer industry does not
emphasize energy use or efficiency, consumers do not
have ready access to the information needed in order to
make informed decisions, and energy analysts and pol-
icy makers have only begun to identify the importance
of this particular energy end use. Policies proposed for
addressing other types of household electronics
(OECD/IEA 2009)andgameconsolesinparticular
(Webb et al. 2013) could be beneficially applied to
gaming computers as well. More vigorous energy pro-
grams and policies are needed to mitigate the energy
consequences of the very fast-growing worldwide mar-
ket for gaming computers.
Acknowledgments We thank Jon Green, Oliver Kettner, Jon
Koomey, Bruce Nordman, Ted Pollak, Brian Strupp, and three
anonymous reviewers for their support and constructive
comments.
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