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TEST RESULTS CONTINUED
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 on our test system. 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 system power under CPUBurn with just the integrated graphics is subtracted from the system power under CPUBurn with the add-on card, we obtain the increase in idle power of the add-on card. (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 ATITool 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 ATITool should not skew the results, since the CPU was running at
full load in both systems.
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Power Consumption Comparison: HD 3850 vs. HD 3870
vs. X1950XTX
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GPU State
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HD 3850
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HD 3870
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X1950XTX
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AC
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DC (Est.)
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AC
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DC (Est.)
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AC
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DC (Est.)
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Idle
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+13W
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+11W
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+20W
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+17W
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+49W
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+42W
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Load
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+64W
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55W
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+84W
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72W
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+131W
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110W
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Both cards drew much less power than the 18-month old X1950XTX
but the HD 3850 stood out with less than half the consumption on load. Idle
power consumption was excellent, again especially the HD 3850. +11W at idle over the integrated graphics is no
small achievement.
Video Playback
The video playback was equal as expected, both cards taking full advantage
of UVD. It has been our experience that the core, memory, and shader speeds
do not affect playback. CPU usage during H.264 decoding was especially low —
at about 3% one could easily mistake the system as being idle. Considering the
test system uses an old dual core Presler processor, these results are excellent.
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Video Playback Comparison: HD 3850 vs. HD 3870
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Video Clip
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HD 3850
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HD 3870
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Mean CPU
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Peak CPU
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AC Power
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Mean CPU
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Peak CPU
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AC Power
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H.264
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3%
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8%
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~98W
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3%
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9%
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~105W
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WMV3
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28%
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38%
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~109W
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27%
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41%
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~118W
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WVC1
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55%
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80%
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~125W
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50%
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78%
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~130W
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HDMI OUTPUT
The Palit Radeon HD 3870's HDMI ouptut (via DVI adapter) offered all the
standard and widescreen resolutions between 800x600 and our monitor's native
resolution of 1440x900. Unfortunately the image quality was poor — the
text was fairly blurry at all resolutions. It was completely unacceptable for
2D use. Video on the otherhand, looked satisfactory.
The audio functionality did not work at all. ATI claims the HD 3800 series
has its own 5.1 audio controller built into their cards (Palit lists it in its
specifications as well) and their DVI to HDMI adapter is designed to carry audio,
so it's unclear what is the cause of this issue. It could simply be that Palit
unwittingly included a generic adapter that isn't wired to carry audio.
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