30fps vs 60fps, GPU vs CPU (Gaming)

by uberfoop , Seattle-ish, Thursday, May 25, 2017, 19:44 (2739 days ago) @ Cody Miller

Programmers can correct me if I'm wrong, but the CPU has to generate the display lists to send to the GPU for rendering. This is why even though 4 player split screen is the same number of pixels, you get slowdown. The CPU is assembling 4 display lists instead of one. The GPU can't draw what it doesn't get, so there is inescapable overhead in improving the frame rate.

That's part of it.

Even as far as rendering goes, there's lots of extra work on the GPU side. Doing two small tasks takes longer than one big one, since context switches and stuff happen. Small polygons are more expensive to draw (relative to their size) than big ones due to how GPU rasterizers work, and LOD systems are never 100% perfect.

I don't have any exact data to back this up, but I wouldn't be surprised if Halo 3's geometric simplicity is a big part of why it's so relatively uncompromised in split-screen. Less things in the scene means less duplicated work.