Also you should check whether the roms are compatible with the newer mame versions or else you might see a significant number off the list and have wasted space.
You could also try a mame version optimized for amd ( 0.120u4 latest build). It gives an increase in more demanding games
If you run some games in zinc instead of mame (get the zinc rom versions) or naomi emulators the processor would be fine.
But buying a new pc for mame games and overclocking the processor is a little extreme.