Xbox is 3.2Ghz Xenon Triple core hyperthread In-order processor. (it processes instruction in order unlike pc processors) It has a theoretical peak performance of 115.2 gigaflops.
Playstation 3 is a 3.2Ghz Cell based processor which consists of one Power processor and 7 'co-processors'. PlayStation 3's Cell CPU achieves 204 GFLOPS
Interestingly, IBM had a hand in both processors as they are both developed from the PowerPC processor..