So yes trying to play openttd and it lags with intel hd 4000 graphic, used switchable graphic options for pc to see if it is any better and it still says i use the intel one instead of amd radeon hd 7650m.
The game lags with the intel graphic unless i turn off the hardware accelerator then it doesn't lag.
So is there anyway to change it to discrete graphic ingame?

Or anything else i can try?

Can you raise an issue on their github? Or see if there's similar issues already?

Didn't register there yet to raise such an issue but i didn't find any info on such an issue when i searched the open ones.

I'd also give a glance over the TT forums, but that may prove a bit fruitless. Because there's a lot of grognards there.

Oh, uh...do you know by what means it's attempting to display by? SDL, OpenGL, et al?

Says something about win32 opengl
What is SDL?
Also without hardware acceleration the game works clean but i wonder if it used my discrete graphic card how would it look like or work like?

I don't think you should expect much. The game has a hard upper framerate, and it only uses about 255 colors overall. It is a rather old game. ;p SDL is Simple Direct Layer, it's a middleware for graphical display. Clumsy at times, but works great for simple 2D.

Yeah. It's just 2D. Predates Roller Coaster Tycoon, originally.