I actually don't think that a PC game exists that won't run on that hardware. The largest hardware requirement I have ever seen on a game box was 800 mhz processor and 32 MB of video ram.
Kind of reminds me of the time that someone on here bought this MASSIVE gaming system and posted on here wondering if it would be good enough to at least RUN Golden Tee Golf for PC.
The funny part is that Golden Tee PC came out like 8 years ago, and will run on a 486, but recommends a pentium 100 for optimal performance, and doesn't use any kind of 3D card.
And also, generally on a Mame cab you can scrimp a bit on the graphics card end of things, even if you ARE playing PC games, mainly because they tend to look better inside a cab at no bigger than 800x600.