Not really.
Vista SUCKS. I mean i just hate the OS. its way to complicated so I had to downgrade back to XPpro. i say stick with XP. Its a lot better and games are more compatible with Xp then with Vista, and so are most windows-based applications.
This sounds like typical Vista rubbish from the great unwashed.
I have run Vista since launch on several custom PCs with a range of hardware and never had a single lock up, and I'm not kidding. I run both x86 and x64 also.
If it is "too complicated" for your little mind then I'm sorry, the world keeps progressing and adding more functionality, what a burden.
Vista is prettier, more stable and better to use than XP and I mean that sincerely.
Go to Vista if you want a more modern OS than XP, that means you need better hardware (as always).
EDIT: as far as the OP's question goes, no it wont make games run faster, but if you are a serious gamer then only Vista supports DX10, XP does/will not - that alone is worth it.