you're saying the ps2 isn't powerful enough to emulate psp?
it certainly is, only problem is there isn't an emulator.
yes, ps2 is not powerful enough to emulate psp.
psp definitely loses in raw cpu power comparison against ps2. ps2 has monstrous bandwidth between cpu, system ram and gfx ram and can process insane amounts of data on-the-fly. that was the main goal of ps2 design.
but it won't help with psp games, since they do not have such requirements. also ps2 architecture is mostly optimized towards 3d transforms of non-repetitive data, which also does not help with emulation (keep in mind that ps2 snes emulator does not achieve full framerate in most games), which is usually a complex operation of repetitive data, usually requiring a lot of caching.
psp is designed to be less power-hungry and it has totally different design. in that department psp is slower, because it was designed to conserve power, and be a small device (low power, low heat)
that said, keep in mind that psp has a dedicated multimedia chip, that can handle dvd resolution h264 movies. i'm not sure what can it also be used for. and the main psp cpu has higher clock speed than ps2 cpu.
in order to properly emulate totally different cpu you usually need a machine few times faster. the more differences between host and emulated hardware - the more overhead.
also keep in mind that emulator itself takes some ram. after it would start, you would have less than 32mb of ram left on the ps2. i'm not sure how much ram do psp games actually use, but that would already be a problem.
