the regular Atom processor (1,6Ghz)was barely able to run Vista (and Win 7); what makes intel think a 1,2Ghz will be any better?
Good enough for linux.
Windows XP was on the edge with previous Atom 1,2Ghz processor, barely allowing you to watch youtube video's in Firefox,while IE just requested too many system resources for the tiny processor to handle all.
As far as the Z550,it'll probably be too expensive, but will hopefully reduce the price of the 1,8Ghz Atom Z.