A Xbox360 emulator isn't really possible, though a PS3 one can be made and would probably run at full speed on a P4 2Ghz, 512 mb RAM and Geforce 4MX, there is a PCSX3 in development though unfortunately its fail cause it currently needs a core2duo 2Ghz 2 gb ram and geforce5200 and plays 90% of the games witch is fail imo since the requirements are way to high for a ps3 emu.