Ok after trying a few SNES games (using SNES9XGP) these are the ones staying on my GP32. There were many others I took off as they just ran too slowly.
Mario All Stars - Playable with sound off
Mario World - Playable with sound off
Final Fight - almost full speed with sound off
Final Fight 3 - almost full speed with sound off
Street Fighter - almost full speed with sound off
Worms - playable
Sim City - slow with sound off but playable
Super Turrican - Playable with sound off
Mario All Stars - Playable with sound off
Mario World - Playable with sound off
Final Fight - almost full speed with sound off
Final Fight 3 - almost full speed with sound off
Street Fighter - almost full speed with sound off
Worms - playable
Sim City - slow with sound off but playable
Super Turrican - Playable with sound off