I don't suppose he will read this but i have an idea:
Im guessing he made it use cache because some of the ROMS are too big. You don't need the cache file at all.
1) You make the cache file as normal.
2) You then delete files 13-20 in the ROM folder taking the file size down from 22MEG - 8MEG.
3) You then put all the files out of the cache folder you have made back into the mvscu folder. (Total file size = 18MEG)
Now he is the idea. Instead of pointing the emulator to the mvscu_cache folder just keep it pointing at the mvscu folder in the roms folder. Everything will be loaded before the game loads, which stops the PSP having to read the memory stick all the time which causes the lag.
What do you think? Do you think it will work? If it works this could be used on all the bigger ROMS that lag.