My first thought when reading about this is I know NVIDIA makes rack mounted devices with their "Tesla" GPU for HPC applications like this. I would feel more confident with hardware designed for what the Airforce is trying to do and it seams like the Tesla servers would have a lot less wasted hardware and may be more efficient in a server environment.

So I googled it and found out IBM already moved from Cell to Tesla last May.

http://arstechnica.com/business/news/2010/05/ibm-cheats-on-c...

I'm also curious how AMD's new APU will affect this market.

http://news.ycombinator.com/item?id=2067057

The reason that most of these mini clusters made of ps3's came up is because Sony was subsidizing a good percentage of the cost.

what a waste. They could have bought IBM BladeCenter solution with the same processors, but with Infiniband and more memory.. instead they have a big toy.

With greater power consumption and a much higher cost.