I have no experience with GPUs, but I once read something that indicated that the driver, in fact, has a lot of proprietary code in it. For example, nVidia oft

I have no experience with GPUs, but I once read something that indicated that the driver, in fact, has a lot of proprietary code in it. For example, nVidia often releases driver updates after a new game is released that can give 10-25% performance boosts in those games. That's not because it's running the GPU faster, that's because of optimizations within the driver on how GPU commands get processed by the GPU. Someone with more knowledge about this please correct me if I'm wrong.