Swapped USB card exactly same issue.. Don't suppose anyone has come across this?

Ok so with usb soundcard it runs flawlessly (slight screen fuzziness aside) so somehow the audio is causing an issue.

Hi, On with my first Gameboy Zero build and I’m almost done. Problem is audio is a little glitchy and after playing a little of certain games or just launching others the PI zero seems to grind to a halt and the audio gets very scratchy. I really feel like this is an audio issue so i’m Going to try ...