Well, the notebook version of the processor supports Windows 2000 so I
can only assume that the desktop version also would:
Operating System Compatibility
AMD Athlon 64 X2 dual-core processors for notebook PCs are designed to
be compatible with Windows® XP Professional x64 Edition, Microsoft
Windows® XP Professional, Windows XP Home Edition, Windows 98, Windows
ME, Windows NT®, Windows 2000, Linux®, and other PC operating systems,
including Windows Vista™.
http://www.amd.com/us-en/Processors/ProductInformation/0,,30_118_9484_15184,00.html
As I said earlier, usually it isn't the processor that is the problem,
it's the rest of the hardware that the processor is mounted on. I agree
with you however that it would be better to use a newer operating system
on these new computers. It is getting increasingly difficult to get
older operating systems to properly install on new hardware.
John