You mentioned that With most problems the performance difference between CPU and GPU implementations is huge, I'm actually quite interested to which extent the performance gap goes. Would you have any numbers or articles about this (for example, on the example of texture 3D-rendering)? Thanks for your answer and for your time!

You're right, my tags and title were misleading, removed games and added performance/optimization. I didn't mean that it was exclusive to games, but that's where I noticed it. I thought it would have to be very hardware-specific too. Thanks for your answer and links!