The Xbox360 for example was a tricore with HT clocked at 3.2Ghz in 2005. (Back then we had X2 and P4D.)
Xbox720 (if this is right) will be an 8 core low performing 1.6Ghz chip in 2014/2015. A product that is awfully slow even by last years standards.
do you really think the 360 CPUs is superior to the 2005/2006 PC CPUs?
compare that thing to a Core 2 Duo...