After testing 30+ PS1 games on PSP, psxonpsp660.bin gives the least crashes, best audio sync, and smoothest cutscenes. If you’re still using pops 3.xx or 5.00, upgrade now. Pair it with POPSLoader to keep per-game configs.
: Ensure the filename is exactly as stated (case-sensitive on some systems); it is typically all uppercase with a lowercase .bin extension. psxonpsp660bin better