ATI HD3850 & HD3870: Improved Acoustics & Power Efficiency

Graphics Cards
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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.

Power Consumption Comparison: HD 3850 vs. HD 3870 vs. X1950XTX
GPU State
HD 3850
HD 3870
X1950XTX
AC
DC (Est.)
AC
DC (Est.)
AC
DC (Est.)
Idle
+13W
+11W
+20W
+17W
+49W
+42W
Load
+64W
55W
+84W
72W
+131W
110W

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.

Video Playback Comparison: HD 3850 vs. HD 3870
Video Clip
HD 3850
HD 3870
Mean CPU
Peak CPU
AC Power
Mean CPU
Peak CPU
AC Power
H.264
3%
8%
~98W
3%
9%
~105W
WMV3
28%
38%
~109W
27%
41%
~118W
WVC1
55%
80%
~125W
50%
78%
~130W

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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