I am in the midst of a couple of waves of upgrades for my 2nd MAME cabinet (built in 2005). Afte rit sat idle for about 2.5 years due to a new job out of town, a move, and then spending 10 months finishing my basement, it was in dire need of some help. Some of the wiring came loose, etc. Anyway, I was about 4 years behind on MAME too.
So I went from an AMD Athlon XP (single core) 2500+ (1.8 GHz) to an Athlon XP 2900+ (2.0 GHz) and a fresh load of Windows XP due to a primary hard drive failure. Didn't see much improvement, but should have been about a 13% jump in CPU processing. Then again, the machine was dead when I made the upgrade and I hadn't played in a couple of years. That is where it sits today, however...
Tonight I am upgrading from the single core Athlon XP 2900+ (again, 2.0 GHz) with some cheapo video card, and 768 MB of RAM, to a newer motherboard running an Athlon X2 (dual core) 5000+ (2.2 GHz) with a video card that I just upgraded in my primary desktop PC that I use for gaming and a fresh pair of RAM sticks to get it to 2 GB. Going to install yet another fresh version of Windows (TinyXP this time) and I've got an external hard drive with Hyperspin and a bunch of other emulators besides MAME on it. The processor is capable of a 193% increase, but I am not sure how much of that MAME will actually tap in to.
For me, this isn't a killer MAME machine. I feed it upgraded hardware that is trickling down from my primary desktop PC. I am about maxed out with my dsktop PC and its own upgrades and will need a full fresh build to go any further. I am hoping that for my regular gaming, plus video/photo editing, that the quad core 3.6 GHz setup with new video card lasts a while, but at some point, those will hit the MAME cabinet.
I wonder what upgrade in performance I might see. Probably not as much as others.
I am waiting for the day that I can play Stun Runner. I used to love that game as a kid, and to me it has been that game that has been out of reach for SOOOOO long on a MAME cabinet.