Off (or set to 1 if your device is low-end). Auto-frameskip: Unchecked.
If you experience lagging or audio tearing while playing a compressed file on an emulator, tweak these settings for smooth 60 FPS gameplay: crash mind over mutant psp iso highly compressed
: Connect your PSP to your computer via USB, then transfer the ISO file to the "ISO" folder on your PSP. Off (or set to 1 if your device is low-end)