Assuming you have the E8400 Wolfdale or something similar to that then you should be good for updating. It won't get 100% on the most demanding stuff, but there's also TONS of games and fixes that have been added over the last 3 years that will make updating worthwhile.
Ditching XP 64 is a good decision.
The only concern to consider is DirectDraw is gone and MAME throws an error if your GFX card is really ancient. Something about power of two shapes or something (I can't remember now and am too lazy to google it)
Basically you're gonna gain so much more than you'll lose by running the latest version. Go for it!