Make sure your not converting from the mem stick- have all your roms and the converter/cache folder on your HDD-i had a few issues when trying to cache files from my memstick-too slow for it.
how powerful is your PC? i'm using a VAIO VGN S1laptop and it handles it with ease.
I reckon NJ's got a few more plans for the PSP. there are still lots of early 90's arcades for him to emulate. Anyone interested, check out SNK-CAPCOM dot com. looks fairly new and has some good info/reviews.
I would love it if he had a go at the Sega chipset that ran the virtual on games- i'm almost certain this is totally impossible for PSP, though, as it was only released around in 2000 and was in full 3D.
I'd love to see a 'Virtual On' UMD game for the PSP, it's almost crying out for ad hoc challeng mode. I spent 12 hours in Sega world, Sydney for a bet and mostly played that with my pal Dan. Felt really sick the next day