>Why would that matter?

The game devs are going to spend all their time & effort targetting amd/nvidia. Custom code paths etc.

It's not a one size fits all world. OpenCL etc abstraction are good at covering up differences, but not that good. So if you're the player with <10% market share you're going to have an uphill battle to just be on par.

> The game devs are going to spend all their time & effort targetting amd/nvidia. Custom code paths etc.

From my experience they target NVidia and Consoles. AMD might get a look at the code just before release if they notice any big problems.

I'd be surprised if many Gamedevs even pick up the phone for an Intel GPU developer.

Consoles use AMD GPUs for years now.

Yeah, but the different APIs and system integration (shared memory) means many of the specific tunings and optimizations don't carry over very well.