Dell Precision 670 | WIN 64Bit OS Upgrade Possibilities?

By doing a bit of research I found out that Windows 7 is not recommended for a Dell Precision 670 desktop, and by looking at available drivers WinXP64 is as far as Dell's driver support goes. It does not even get into Vista drivers which in some cases are supported by Win7.

Is XP the end of the road for this machine when it comes to drivers and such?

Any feedback and tips are appreciated!