Well MAME is processor dependant, not video card dependant, so the important number on your system is the 600 processor, not the ge force 3. In your case you got a very fast video card and a very slow processor, which is the reverse of what MAME needs. Your 600 will be fine for 80's games and some vertical scrolling shooters, but for processor intensive games like MK, you will probably have to disable sound to get 60 fps. You may be able to lower the sound quality to get a playable framerate, but depending on your mobo, you will probably just want to upgrade. 1.3 gigahertz processors are less than $40 nowadays.