A popular method involves using a beta port of the emulator adapted for the PS3.
The PS3 is notoriously bad at emulating the Nintendo 64. Here is why the prospect of a "hot" (optimized, playable) PKG is such a big deal in the underground scene:
If you search for "Mario Kart 64 PS3 PKG hot," many links will redirect you to pre-configured RetroArch builds. These are "hot" because they are updated frequently to fix the abysmal frame rate most N64 games suffer from on the PS3.
: Check out Reddit's Gaming4Gamers for threads on games with must-play stories, like Xenoblade Chronicles or The Last of Us .