Sorry my bad, so used to talking about AMD, that I... that I... have been brainwashed.
Back to what he said HT emulates having 2 CPU's so then you will have 4. Depends what $40 is worth but the performance gain is negliable.
XP would defiantly work. I have the AMD 3000 on 32bit windows and it will work better than 64bit for me.
I remembered why there is a performance drop now.
If you get a true 64bit game than there will be a performance increase but ever other game will have to 'emulate' 32bit, which takes away FPS.