Originally Posted by darksideleader
26 more watts than the GTX 280 not that much really.
ATI's idle power consumption on the 4800 series should get better with the next driver update. Idle power consumption would be identical with the dual gpu counter part because when the gfx card is doing nothing, it basically disables one gpu.
load power consumption can vary though. Most of the time we won't using the 2nd gpu at 100%. So we gotta keep in mind 260w is that max, but most of the time, we won't see it go that far.
The gtx280 tdp is 236W, but actual power consumption is ~175-200W depending on clock speed. The 4870 TDP is 160W and actual power consumption is ~150W. So even with a conservative TDP of 260W for the R700, it will probably consume about 250W which is noticeably more than the gtx280 (but noticeably more performance too
). It should be decent performance/watt, but still, these cards will be monsters.
It's true that the R700 won't always draw 250W, but I've seen examples of 4870 crossfire drawing twice the amount one 4870 would (so ~300W for the GPUs). You always plan for the maximum.