> I've already launched Michael Jackson's Moonwalker and pressed f11. It was showing > approximately 88-93%.
Well that's definitely the problem. There's no way to avoid sound stuttering at that speed. That's not a vsync issue either because mwalk us 57Hz so you'd be at 105% speed or so if it was throttling to 60Hz.
I get more like 900-1000% speed on my 4.4GHz i5 on moonwalker, so if you're not running it on a potato I guess your PC would be fast enough.
You are running on a PC right? Not some ancient MAME version on a raspberry pi or something?