It was 50% in pcars on my Xfire 290s.
Call it 20% seeing as your so into defending AMD...but it was 20% more than AMD could be bothered to get out of their own drivers. Didn't leave me very impressed! Oh and does Freesync even work today for Xfire users...what a joke!
this is another good point. AMD made so much fuss about Nvidia and project cars and threw out all sorts of unfounded accusations which both nvidia and the game developer quickly disproved. Turns out there were just driver issues affect AMD cards, but now we have a situation where some review sites purposely ignore project cars as if it is some kind of purposeful nvidia sabotage. that then gives a completely unfair picture of the performance.
Do we see AMD making a public apology that it wasn't Nvidia's fault but a driver issue on their side?
Same with hairworks in Witcher 3. All sorts of nonsense thrown out by AMD which the fanboys lap up. FuryX is released with something like twice the tessellation performance due to architectural tweaks. Now the Witcher 3 with hairworks switched on is one of the games AMD does best, switching hairworks on increases the performance over Nvidia, that is where they see some of the biggest performance gains. Yet some how AMD get away with their PR shenanigans blaming Nvidia sabotage.
The companies are bad as each other and are both trying to do nothing more than maximise profits. Buy what ever works for you. Since I use linux that typically means Nvidia, but my current machine is a Mac i27" with anAMD GPU.