Hello! I have a cpu in my mac pro early 2009 (still old, but pretty strong) and it says: "2 x 2.26 GHz Quad-Core Intel Xeon"
Does that mean that it's an octa core cpu?
A CPU model would be useful. There are tons of Xeons.
But generally I would say that it means you have a dual processor setup - so you don't have 1 octa core processor, you have 2 seperate quad core processors.