Here is a set of particular options to set in your Basilisk II prefs file
( "$HOME/.basilisk_ii_prefs" for Unix and "BasiliskII_prefs" for Windows ).

• cpu
  

  You currently have to set it to 4, i.e. for 68040 emulation. The JIT compiler will not work otherwise (actually, it gets disabled once MacOS has booted) or will even crash if you use one of the old versions from October, 2000 or the new release from January, 2001 :-(

• jit
  

  If set to true, enable the JIT compiler. Otherwise, we revert to the (slower) interpretive way.

• jitcachesize
  

  Size of the translation cache. Set it for example to 2048 (the minimal value) in order to get a 2048 KB translation cache. Now that we use Lazy Translation Cache Flushing, it is greatly profitable to put a higher value here. For example, I use a 8 MB translation cache and I get higher speed than with only 256 KB. BTW, Lazy Flusher 2 will aim to get the same speed with a shorter translation cache but it is not implemented yet.

• jitfpu
  

  Flag set to true if you want to enable JIT compilation for the FPU. This option has no effect with the old releases. Starting from November releases, JIT Basilisk II supports compilation for FPU instructions.

• jitlazyflush
  

  If set to false, use the old way to flush the translation cache that consisted in flushing whenever the 68040 processor requests it. If set to true, use the lazy translation cache flushing method that consists in keeping the translated code as long as possible, i.e. recompile only the blocks that changed.