In the presentation ATI gave on its Radeon HD 4890 pre-launch, it admitted that the board’s load power would be up as a result of the higher clock speeds, to the tune of roughly 30 W. Idle power, however, was said to be down 30 W from 90 to 60 W.
That was a much more significant number in our eyes, since the card would spend a majority of its time in that lower-power state and, as a percentage, the drop from 90 to 60 W was much larger than the load increase from 160 W to 190 W.
Nevertheless, our system power measurements do not reflect the idle power consumption improvements. Our load numbers do jump 25 W, which is close to the 30 that ATI cites. But the idle power sitting on the Vista desktop is actually 2 W higher than the Radeon HD 4870 1 GB. The 512 MB card is higher than both, strangely enough. This was one of the original card samples, so it’s entirely possible that it isn’t optimized for power as the retail boards being tested alongside it.
The GeForce GTX 260 Core 216 trumps the entire ATI lineup, both in idle and load power consumption. The 55 nm GTX 285 turns in even better idle results, though its load consumption jumps in response to its increased complexity.