Laggy play on PS1 mod chip

I soldered a mod chip in my PS1 a couple years back and have mostly played Ape Escape on it and it plays fine.

Last night I tried burning Final Fantasy 7 disc 3 to use my old 20 year level 99 save. My actual game got stolen from me in a car theft back then so I downloaded this from a Rom site.

I used the program Burn on a mac to burn the .bin and .cue file

Initial burn didn't play at all. Tried again on the slowest burn speed and the game booted but plays like ass with tons of...

Laggy play on PS1 mod chip