Wow, a lot of comments.
First off, I have some decade old AMD hardware that is STILL kicking it.
Secondly, I have every dead motherboard/processor I have sitting in my closet (4 of them at last count) is Intel hardware.
Third off, overclocking the computer used in your Mame cabinet is silliness. The fact is this, once that Mame cabinet is DONE, then it might very well be around for 10 or 20 years, and there is no reason to do anything that would accelerate the death of the hardware, especially since it is just silliness, since Mame games basically fall into three categorys, stuff that will run on a 700 mhz pc (basically everything), stuff that won't run full speed on anything (50 games or so), and stuff that isn't properly emulated which must somehow be mentioned (I am not sure why, ask Howard Casto).