How much GPU is used by PPSSPP?

[xsacha]

Basically you need a CPU fast enough to generate 60 frames (run the CPU loop) for that game-- usually quite a weak CPU.
Then you need a GPU fast enough to render those 60 frames -- usually a fairly decent GPU but depends on the game.

You wouldn't associate percentages with them. It's more a threshold thing.

You can get 60 VPS and 0 FPS with no GPU, for eg.
You can get 0 VPS (and hence 0 FPS) with no CPU, for eg.

A lot of emulators don't use the GPU at all for the emulation (like shaders). Basically PS1 and everything weaker.