http://wiki.libretro.com/index.php?t..._Compatibility

Seems Super Punch Out is fine.

Regarding the stuttering it seems you are just pushing the CPU, lower the resolution.

If you want accurate PSX emulation use the mednafen psx core in Retroarch, it runs almost all PSX games perfectly.

Mednafen is CPU dependent but it should not act like BSNES, I can use mednafen psx just fine and its not putting a huge load on the CPU.