I know Unreal Engine uses Nvidia PhysX for physic simulation in games. As you know, PhysX has been created by Nvidia, and I’ve read that games created with this technology run less performant on ATI.
But on this forums, some people told me that UE4 compile Nvidia Physx code for CPU.
Is this true?
This posting from Tim Hobsonanswers your questions
What about UDK?
Judging by THIS I would say it is CPU based as well since it mentions the implementation being “Cross-Platform” and is “even in CPU PhysX and console games”, plus it doesn’t mention the term GPU anywhere in the article.
This does not mean that you can’t implement the PhysX library separately for the GPU in UE4, you have the full source code at your disposal.
PhysX runs on CPU in UE4, so performance is the same regardless of GPU. For UDK there is PhysX acceleration on Nvidia GPUs