From the Docs
PJ64 1.4
"Register Caching"
Possible settings: checked or unchecked
- default setting: checked
- generally recommended setting: checked unless it causes failure
Probably the recompiler's most significant optimisation technique, register caching usually dramatically improves the efficiency of the recompiler without side effects. The reason this is included as an option is that sometimes register caching will produce an error in a game. Register caching can cause many kinds of obscure errors, such as events in a game not triggering, or a game becoming stuck in a loop, aswell as obvious errors such as a crash. If you find you are having stability problems with the recompiler and not the interpreter, try disabling register caching to see if you can get past the point/game with at least some of the performance of the recompiler.