I most recently tested Mupen64 on a P4 3.0G 2G ram NVIDIA Geforce 7600 GS system running Fedora 7. Using various plugin combinations and the lowest possible resolution I was not able to run any games at a decent speed. I also had constant crashes and lockups. These are basically the same result I had on my old Athlon 1.2G Fedora Core 4 system.
Note: I have read elsewhere that others have operated Mupen64 at full speed??