It shouldn't, though... I remember reading that the speed of the PSP environment on the Vita is actually far more powerful than the original PSP ever was, but you might just need to adjust the speed setting in the exploit itself. I had it fully cranked and didn't notice any speed issues, but I never played any emulators, just a handful of PSP games.
Maybe I'll mess with the settings some more, I just remember Mario Kart running better on my PSP Go.
PSP games are flawless(the ones I've tried), no complaints with that.