This was known a long time ago. A big debate for the time before and after the release of the PS3. The Cell CPU was being used and could produce a insane amount of processing power. The Cell CPU is assumed to running at 3.2 GHz, the clock speed most often cited.
At this clock frequency each channel flows at a rate of 25.6 GB/s.
From
Wikipedia.
Yes it has only 1 true core. But it does something like 218GF (GiagFlop) of processing or something like that. The 360 can do 115GF of processing power. So the Cell is about 100GF higher.
TG Daily - Update: How many FLOPS are in game consoles?