ATI Radeon HD 4770: ATI's First 40nm GPU

Graphics Cards
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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.

Power Consumption Comparison (DC)
Card
Est. Power (Idle)
Est. Power (ATITool)
Est. Power (FurMark)
Asus EN9400GT 512MB
11W
N/A
23W
PowerColor HD4650 512MB
15W
N/A
28W
ATI HD 4670 512MB
3W
50W
60W
ATI HD 4770 512MB
28W
50W
60W
ATI HD 4830 512MB*
18W
80W
87W
Asus EN9800GT 512MB
32W
72W
80W
Diamond HD 4850 512MB
50W
101W
N/A
* sample with unknown number of stream processors

Our power consumption measurements yielded mixed results. Our HD 4770 sample used considerably more power in idle than the HD 4670 and 4830 we tested, but considerably less power than the 4850. (See notes in the conclusions for more thoughts about the idle power.) With full 3D load, however. it drew an impressively modest 60W, 27W lower than our 4830 sample. If the card's performance is anywhere near that of the 4830, this is an impressive feat.

System Power Consumption (AC) During Video Playback
Card
Rush Hour
(H.264)
Coral Reef
(WMV-HD)
Drag Race
(VC-1)
Asus EN9400GT 512MB
112W
110W
137W
PowerColor HD4650 512MB
102W
115W
137W
ATI HD 4670 512MB
94W
105W
129W
ATI HD 4770 512MB
132W
129W
148W
ATI HD 4830 512MB*
108W
134W
160W
Asus EN9800GT 512MB
119W
127W
141W
Diamond HD 4850 512MB
136W
151W
176W
* sample with unknown number of stream processors

Due to the HD 4770's high idle power consumption, video playback was not very power efficient with our system using between 129W and 148W during playback. Only the HD 4850 drew more power on average.



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