If you install Retropie to USB and only boot off the SD, you’ll get less pauses. The rest you pretty much have to go in comparison with the compatibility chart.
I can say for sure that a lot of the PSP minis work just fine, as do the RPG’s like the Y’s series, and that only at 1050Mhz on the Pi 2 for me.
EDIT: Typo on Mhz
