Double Power for the Blue Gene/L

In spite of Apple deciding to take the Power PC out of its computers, this CPU still finds nice machines in which to be hosted.
The Blue Gene/L is a quite convincing example. With as many as 131072 Power PCs, this IBM system is the world's most powerful server (http://www.top500.org/). It has a computing power of 280.6 TFlops (up to 369) and is dedicated to the simulation of nuclear reaction.