Render Scale Performance Question

[o1o101]

Hi quick question,

Would lowering the render scale/resolution only improve performance if the game is GPU bound? Or would it also benefit a CPU bound game?

Cheers

[MartinTilo]

Only if your game is GPU-, specifically fillrate bound.

[bgolus]

If your GPU is vertex count bound, lowering the resolution can in some cases make performance worse!

[UDesoxi]

Hey Ben, we do seem to have issue related to worse performance when lowering the renderscale at the moment. Would you mind explaining this a bit further? Why would it make performance worse, if the GPU is vertex bound?

[kdgalla]

I’m not 100%, but I imagine it’s related to this:

Are micropolygons bad?

Ok, this is more a general question that I stumbled across while looking at the internal Billboard Grass Shader from Unity. Under a terrain, you can set a radius on how much grass/details you want to render. Now I thought they would cull the meshes beforehand and what you see on screen is what the pipeline works with. But after looking inside of the shader, actually a lot more grass gets rendered and grass planes outside of that above mentioned range just get scaled down to 0 in the vertex shad…

See bgolus’s response in that thread.

“Micro” polygons are “micro” relative to the render pixel size, so lowering your resolution can make more polys “micro” then you’d have otherwise.

[UDesoxi]

This is indeed helpful, thanks @kdgalla !