My recommendation is reading the documentation wtih epsxe thoroughly and the faq. Then it just plain depends upon your system configuration. If you're running an nvidia card, use pete's opengl, if a 3dfx card, use lewpy's, if a card incapable of 3d acceleration or is very poor at 3d acceleration then one of the software plug-ins like kazzuya's or pete's, and then finally for all else pete's d3d. Eternal is the most recommended spu at the moment. And you may want to try Pete's cd plug-in. Also different forget to use the search function here to check up on several problems bof4 has and how to work around them.