When compared to the Radeon HD 5870, the new HD 6970 consumed 16.5% more power but given that it was also ~24% faster we find it to be an overall more efficient graphics card. Against the Radeon HD 5970, the HD 6970 consumed 3% less power yet we found that on average it was 15% slower, 26% slower in Crysis Warhead, which is what we used for stress testing.
The Radeon HD 6970 used roughly the same amount of power as the GeForce GTX 570 consuming 1% more when stressed and 4% less at idle. Given that both graphics cards provide similar performance, this time around it seems they are equally matched.
The Radeon HD 6970 got quite hot when load testing with FurMark as it reached 90 degrees, which is slightly higher than the 87 degrees reached by the Radeon HD 5870. The GeForce GTX 570 on the other hand reached just 81 degrees making it considerably cooler when pushed to the limit.