A post on reddit makes the case again that NVIDIA's Gameworks program includes anticompetitive practices designed to hinder the performance of games on competing AMD hardware. This post in particular discusses the impact of a new version of PhysX on Project CARS performance, though there are arguments that how all this works is being misinterpreted. As before, this has resulted in calls for NVIDIA to release source code to help address this perceived wrong, something addressed in a response posted on WCCFTech (thanks Cutter). Here's a statement from NVIDIA's Brian Burke:

GameWorks improves the visual quality of games running on GeForce for our customers. It does not impair performance on competing hardware.

Demanding source code access to all our cool technology is an attempt to deflect their performance issues. Giving away your IP, your source code, is uncommon for anyone in the industry, including middleware providers and game developers. Most of the time we optimize games based on binary builds, not source code.