How do game and software developers optimize their games and programs for specific hardware?

Question

Iron

Sometimes you can hear a similar phrase: "Games are mainly optimized for Nvidia video cards."

I was wondering, how does this happen? Do you need a custom engine for this?

Let's say I'm using Unity, what should that look like?

using Nvidia;

Game game = new Game()(
Nvidia.OptimizeForOurGPUAndRemoveCompatibilityWithAMD(game);

These are all jokes, of course, but maybe Nvidia has some kind of own language for writing shaders, for example?

Answer 1

Additional shader instructions, CUDA, quite possibly texture formats. Perhaps - picking in the drivers and understanding the rendering processes at a low level.
Yes, most often this occurs not only in self-written engines, but in those where some part of the render pipeline is open or editable.

Answer 2

There is a feeling that in the gaming industry no one is doing this at all, it has started - rather to sell it to the store.