Mine is the last of of there product line that has not changed processors, G5 to Intel Dual Core. It's not PC compatible nor do I want or need it to be. My Son has a new MacBook laptop with the newer processor. Other than hardware options I cant see a difference. If your are not familiar the new/older macs below is a link the apples G5 page. Check out the specs and the way the case is engineered and constructed. The darn thing is built like a BMW. Very impressive design.
http://www.apple.com/powermac/
http://www.apple.com/powermac/