Hyperspin is a resource hog.
There is a beta version of Hyperspin (1.4-Beta15) that is available to Platinum members... Apparently it is more efficient (cant confirm yet).
I run the older Hyperspin (1.3) on a Core2Duo (E8400). Running at 1024x768@60Hz full screen (31Khz).
I need to turn down some features to get everything running smooth, but it still looks fantastic.
Planning to upgrade to a real arcade monitor, and likely run at 640x480i (15Khz)
I would grab an ATi HD 4350 (lower 4xxx series), one that is passively cooled. (no noise, less stuff to break). Flash ATOM-15 on it, so that you get to see the entire boot sequence and not rely on the safety features of the JPAC.
I think that you need to avoid really new UEFI based systems, as the ATOM-15 probably wont play nice.
I would see what sort of Core2Duo you can find second hand (high clock speed, lower cores)
or go for a slightly older i5 or i7 setup (without UEFI if you can find it).
Also you might find it easier to use Win7 x64 these days. Most apps have been updated.