Lunar: Silver Star Harmony

[[Unknown]]

Does it not happen at 1x PSP render resolution? Even if it looks bad, this will confirm if it's related to the GPU fillrate.

I generally recommend turning "simulate block transfer (unfinished)" on. It will fix a bunch of graphical effects in many games.

Somehow I failed to ask: are you using texture scaling? Especially if you have it about 2x, that can cause significant lag in some games.
Edit: sorry, you did say you weren't using it.

You're using buffered rendering, right? Not "read framebuffers from memory".

-[Unknown]