A reliable source close to Sony's plans explained the way the Playstation3 works to the INQUIRER.
He said that the computers are made of cells, each one containing a CPU, which will probably be a PowerPC, and eight APUs (vectorial processors) each with 128K of memory.
It will run at 4GHz, producing a not inconsiderable 256Gflops, with the cells connected to the central 64MB memory through a switched 1024 bit bus.
It's still not clear how many of these "cells" will be used in the Playstation3, but Sony reckoned some time ago it could be as many as one teraflop, probably making it a four cell architecture.
Optical links - perhaps even FireWire optical links - could be used to share computing power.
The Playstation3 architecture is similar to the Playstation 2 but with some improvements, such as a larger number of VPUs, each with more memory. The operating system, too, is much improved.
But Playstations will still be very complex to program well, although it's just as well that Sony doesn't want to take the Microsoft DirectX route.
This is a diagram of the system which is filed in the US Patents and Trademarks Office, and snapped from there, with acknowledgements: