Forgetting, for the moment, the advantages afforded by more RAM being addressable, what performance gains are typical with say, vista 64 over vista 32?
Do all games perform better, or does it vary widely? Is there a list somewhere of games or game engines that perform a lot better in 64?
Update:
Thanks for responses so far.
I guess I'd assumed that by now, most of the major game engines (Unreal, Source, Cryengine, etc) had special versions, not only compiled as 64bit executables but also modified to take advantage of the increased power (I'm imagining some lower-level 3d graphics math or physics or something being faster because of techniques that take advantage of the larger address space and/or any new instructions). Thus some games would have a significant boost in performance. Is this not the case?
Best Answer
From what I gather, 64-bit doesn't necessarily mean better performance, assuming that you compare two identical environment which only differ in their bitness. Ofttimes performance will even be on the 32-bit system's side. This is due to the fact that all pointers on a 64-bit system have a larger memory representation (due to the larger address space) and therefor working with them is slower than with 32-bit pointers (though this effect is always true, not just when games are concerned).
However, you shouldn't just trust what I gather. It is much better to trust what Tom's Hardware gather. Their bottom line is something like: "despite claims from proponents of 64-bit it still looks like no-one is writing their game engines to take advantage of it yet - not in a way that creates significant performance gains".