Troubles with C64 games playing at low speed

whenever I try to play a C64 game, no matter which emulator I choose or what game I try to play, the game always plays at a fraction of the speed it should. No matter what settings I change or whether I’m in fast-forward or slow-motion, the games run excruciatingly slow when I try to play them on my gameshell. No other game type does this - it’s only C64. What on earth is going on?

Not to mention, the gameshell itself crashes like crazy half the time I try to play. I haven’t heard of anyone else having issues remotely similar to the ones I’m having :confused: