According to this Newsday report, IBM's built the world's fastest computer based on the PS3 Cell chip.
The machine, nicknamed Roadrunner, is built of 7,000 AMD Opteron processors and 13,000 Cell chips. It's twice as fast, apparently, as the last holder of the record, Blue Gene.
Roadrunner can punch through one thousand trillion calculations per second. Imagine Lara's hair on one of those, eh?