On my old 1.2ghz CPU, indeed Pj64 was rather slow. 1964 with Jabo's Direct 3D8, Azimer's HLE Audio and Azimer/Hacktaurux RSP worked fine with me except for some core problems. Or, you could try Project64 1.5 and change the audio and RSP plugins for the ones I just mentioned, not sure if that's ok to do ^^'