PPSSPP Input Lag

[LunaMoo]

We have an option in system settings called "Force real clock sync" which can help with such problems that some people experiencing on certain systems(althrough making emulation heavier), however in general PSP should never be compared to arcade games with their input and you might not actually suffer from anything above what you would on real PSP already.

If you ment "Street Fighter Alpha 3 MAX" then this review would confirm that this game was particulary bad when it comes to input delay on real hardware, so yeah nothing you can do about it.
Quite likely it's not even a real port, capcom is pretty known to emulate their old games with some extra stretching options and additional content, but their emulation is rather poor/lazy in compare to open source fan made emulators.