SH4 was designed to run in memory up to 2GB, but with mods it can get much larger. There is a utility that will force it to run in up to 4GB in the Download section. I also use a utility program Game Booster 3 that shuts down other memory hogs, and then restores them after you exit the game. I offer this just in case it wasn 't mentioned elsewhere in this thread. Sometimes things get buried on long threads!
Good hunting!
