I was looking at Mac Pros on ebay (to maybe own one ) and this one I was looking at was a 2.66GHz QCX (Quad Core ...) and was wondering what that stood for. So my other question is, is it 2x dual cores for a quad core or 2x quad cores for a 8 core (it's a 2009 model mac pro)? Any ideas? Just wanted to know before I start jumping into the ebay bidding game! Thanks!