Henry (truncated quote) said:
Should really be using XP Pro for a duo processor (2 physical CPU's) system.
Lots of conflicting information going round the web on this so I did a little digging. In short, XP Home does appear to be fine for a dual core processor.
That was the short answer, if you want some verification look below.
Microsoft advise:
Microsoft said:
Link Q. How does this licensing policy affect products such as Microsoft Windows XP Professional?
A. Microsoft Windows XP Professional and Microsoft Windows XP Home are not affected by this policy as they are licensed per installation and not per processor.
Windows XP Professional can support up to two processors regardless of the number of cores on the processor. Microsoft Windows XP Home supports one processor.
So licence-wise it's ok to run Home on a dual core system, and reading between the lines XP Home (and Pro) supports any number of cores on one processor.
Of course Microsoft don't state that explicitly, so further confirmation was required. I looked through forum postings, product reviews and anything else that Google turned up and it was confirmed time and time again by dual core users who have XP Home installed that the second core was detected and used. I found plenty of postings which advised otherwise, but not one of those stated that they were actually running XP Home. Be aware that there is some evidence that you need service pack 2, but since SP2 is needed to handle power management in dual core processors anyway, that should hopefully be a moot point for the vast majority of dual core users.
Shawn Holwegner has posted some screenshots of his dual core XP Home system which confirm that both processors are actively used. You can view Shawns site
here. From all of this rooting around I'm as confident as I can be without personal testing that XP Home supports at the very least a dual core processor, and it seems quite feasible from Microsoft's comment that it could even handle more. It should be interesting when the Mac Pro gets quad processors