Multi-core

[Bigpet]

The multithreading option only runs 2 threads (and even that's not always faster than running on 1 thread because of the additional synchronization work involved). Because there is not that much work to be done independently of one another. The PSP itself uses something called cooperative multi-threading that allows multiple threads of execution but those threads aren't made to run in parallel, they're made to run sequentially and the threads themselves decide precisely when to switch away. So the threads on a PSP are not independent of one-another.

If you want to use more threads you can turn on software-rendering. It may not make games go faster, but you it'll use all your cores.

Btw. this goes for both the Desktop as well as the Android versions (except there are of course Desktop PCs fast enough to render in software mode).