NVIDIA's GameWorks has been used with several game titles, the most notable of which being Watch Dogs. While NVIDIA boasts GameWorks as offering many advantages, rival AMD has a far different opinion of it, with the company's Robert Hallock recently calling it a "clear and present threat to gamers."
The statement was made in a talk with Forbes, during which Hallock says that the threat GameWorks presents is due to "deliberately crippling performance on AMD products", something that he says NVIDIA is using to "widen the margin" in its favor.
He goes on to state that when a developer decides to work in the GameWorks program, it "often precludes the [aforementioned developer] from accepting AMD suggestions that would improve performance directly in the game code." Hallock goes on to discuss the topic a bit more, and as you might imagine, his claims drew strong disagreements from NVIDIA.
In its own statement to Forbes, NVIDIA responded to the claims via its Director of Engineering Cem Cebenoyan. He goes on at length about the topic, countering many of AMD's claims with statements that they're false to some degree or the other. In reference to Hallock's claim about performance improvements in the game code, Cebenoyan said:
"Thousands of games get released, but we don’t need to look at that source code. Most developers don’t give you the source code. You don’t need source code of the game itself to do optimization for those games. AMD’s been saying for awhile that without access to the source code it’s impossible to optimize. That’s crazy."