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POWER
The power consumption of an add-on video card can be estimated by comparing
the total system power draw with and without the card installed. Our results
were derived thus:
1. Power consumption of the graphics card at idle - When CPUBurn is
run on a system, the video card is not stressed at all, and stays in idle mode.
This is true whether the video card is integrated or an add-on PCIe 16X device.
Hence, when the power consumption of the base system under CPUBurn is subtracted
from the power consumption of the same test with the graphics card installed,
we obtain the increase in idle power of the add-on card over the
integrated graphics chip (Intel GMA950). (The actual idle power
of the add-on card cannot be derived, because the integrated graphics does draw
some power — we'd guess no more than a watt or two.)
2. Power consumption of the graphics card under load - The power draw
of the system is measured with the add-on video card, with CPUBurn and FurMark
running simultaneously. Then the power of the baseline system (with integrated
graphics) running just CPUBurn is subtracted. The difference is the load power
of the add-on card. (If you want to nitpick, the 1~2W power of the integrated
graphics at idle should be added to this number.) Any load on the CPU from FurMark
should not skew the results, since the CPU was running at full load in both
systems.
Both results are scaled by the efficiency of the power supply (tested
here) to obtain a final estimate of the DC power consumption.
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Power Consumption Comparison (DC)
|
|
Card
|
Est. Power (Idle)
|
Est. Power (ATITool)
|
Est. Power (FurMark)
|
|
Asus EN9800GT 512MB
|
32W
|
72W
|
80W
|
|
ATI HD 4830 512MB*
|
18W
|
80W
|
87W
|
|
Sparkle GTS 250 1GB
|
22W
|
87W
|
124W
|
|
Diamond HD 4850 512MB
|
50W
|
101W
|
N/A
|
|
Asus ENGTX260 896MB
|
35W
|
122W
|
N/A
|
|
ATI HD 4870 1GB
|
67W
|
121W
|
134W
|
|
* sample with unknown number of stream processors
|
Our Sparkle GTS 250 1GB sample exhibited relatively low idle power consumption
compared to other gaming-oriented cards. Among tested card the same league,
only our HD 4830 sample consumed
less power when the system is idle, and even then only 4W less. When stressed
however, the GTS 250 can use as much as 124W DC by our estimates.
|
Video Playback Power Consumption (AC)
|
|
Card
|
Rush Hour
(H.264)
|
Coral Reef
(WMV-HD)
|
Drag Race
(VC-1)
|
|
Asus EN9800GT 512MB
|
119W
|
127W
|
141W
|
|
ATI HD 4830 512MB*
|
131W
|
139W
|
153W
|
|
Sparkle GTS 250 1GB
|
133W
|
136W
|
164W
|
|
Diamond HD 4850 512MB
|
123W
|
134W
|
160W
|
|
Asus ENGTX260 896MB
|
136W
|
151W
|
176W
|
|
ATI HD 4870 1GB
|
183W
|
176W
|
199W
|
|
* sample with unknown number of stream processors
|
For video playback, the faster 3D cards all draw relatively high power. The
GTS 250 holds its own against its main rival, the HD
4850. In the big picture, this probably isn't going to sway any gamer
to one card or another. The faster the card, the more power its going to draw,
whether during video playback or intense gaming.
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