run through the config menus, if you dont understand what something means leave it alone, i found that emulator to be quite self explanatory. if you can try to stick to a direct 3d renderer
i would enable it if you can otherwise leave it. a lot of the options for the emulators ive used tend to rely on a little experimentation to find what works best for your hardware
i dunno, every emulator has different options and some will call the same feature by a different name. im sure its not gonna make or break the emulator either way