AMD's Radeon beta drivers greatly improve Witcher 3, Project CARS performance
Both games were built with some sort of Nvidia software included; Project CARS employs PhysX, while Witcher 3 utilizes various GameWorks middleware technologies, most notably HairWorks and HBAO+. That's led to accusations of Nvidia and the games' developers intentionally crippling performance for AMD Radeon users--something that's only kind-of-sort-of true for The Witcher 3, and an accusation that Project CARS' creators strongly fought back against. The latter, in fact, gently tossed shade at AMD for the utterly abysmal performance of Radeon cards in Project CARS.
"Testing of the game with different driver versions has produced a variety of performance results on both nVidia and AMD hardware. This is entirely to be expected as driver changes cannot always be tested on every game and every card, and this is the reason why both companies produce game-specific driver profiles, to ensure that they can get the best out of the game."
Nvidia had WHQL-certified Game Ready drivers available for the launch of both titles.
But ignoring all the drama, it's nothing but a good thing that the Catalyst 15.5 beta drivers are out. AMD says you can expect to see up to 10 percent performance gains in The Witcher, and up to 17 percent gains in Project CARS.
Radeon users on Twitter, meanwhile, indeed report seeing large performance gains in both games. Huzzah!