Why did Sony use the Cell processor in the PS3?

[footbag]

fazz said:

footbag said:
About 7 or 8 years ago, I remember when everyone was saying that all PC processors were going to go cell. In the end it didn't work that way at all, and a lot of companies had to rethink there decisions. The PS3 was so far into planning at that point that they couldn't switch it out.

Eh... what? I think you are referring to something completelly different...

 I'm refering to the Motorola/IBM venture that resulted in the Cell processor for the power PC.  Which at the time was billed as the worlds fastest PC.