I've added a few snes roms to the roms/snes directory. None of the roms load correctly when I try to play them. A few of them won't display at all, others freeze after loading. I'm wondering if I have bad roms, or if I need to make some tweaks to the pi. I'm very new to pimame. I just got it loaded and running last night!
Have you tried altering the overclock and memory settings in rasp-config? Step up the settings a little at a time and test see if you get any improvement.