All off topic discussions go here. Everything from the funny thing your cat did to your favorite tv shows. Non-programming computer questions are ok too.
Hyperthreading, if you really want it, should be supported on any Windows version that supports multiple CPUs since the feature was introduced, probably Win2000/WinXP should be about right.
Windows 2000 handles it (because ive tried it). Windows XP also handles it. And i was informed that NT 4 also supports it if you have a multi processor edition. However im not entirely sure about NT 4.