If we take the 2.8x performance/watt improvement figure by AMD literally, and apply that to say an MSI R9 390X
, we get exactly the same performance as a 390X with a usage of around 92W.
If we assume the figure is exaggerated a bit, and the 480 uses around 120W and has the exact same performance of the 390X, the performance per watt improvement would be 2.1-2.2. I guess that would be reasonable.
If we assume only the 1.7x improvement figure due to FinFET, we come exactly at the 150W TDP of the 480, with the performance of the 390X as a basis.
Considering cards need a margin below their max power usage, and the improvement is 'up to 2.8x', I think it's not unreasonable to expect at least 390X performance from the 480 since we can quite confidently say that it will be at least higher than 'only' the 1.7x performance per watt, closer to maybe 2.1 realistically. Furthermore... If AMD has not been deceptive with its 2.8x number at all, it might even be justifiable to conclude that it won't be (much) less performance than an R9 Fury (non-X) in performance.Edited by NightAntilli - 6/8/16 at 1:19pm