Originally Posted by Ninja Prime
The answer is fairly obvious. Both being limited by a 300w TDP, the company with the better perf/watt chip will be faster. ATI is ahead in that metric by something like 30-40%.
The thing is, no one knows at this stage which will be faster. You can surmise that the ATI part will be (and it might) But we will know soon enough if both cards are almost ready for market.