Fast Game News Online claims Sony has picked IBM's Power7 architecture for its PlayStation 4 console. The site writes this new gaming platform is scheduled for 2012 and that IBM is working on a cost-effective version of the architecture custom designed for Sony's needs.
The only information FGNOnline currently has available regarding specifications and performance is that the PS4 implementation of the chip shall use 6-8 cores, 24-32MB shared L3 Cache, Quad threading per core, and a double precision performance approaching 200GFLOPS.
The CELL chip which powers the PS3 is capable of 15 double precision GFLOPS. This would give the PS4 a performance leap of over 10 fold over it's predecessor.
Interestingly, the primary reason IBM cancelled development on the CELL based PoweXcell 8i is because of SCEI's change of stance. The company wanted to move away from the exotic architecture employed for the PS3 to a more traditional architecture favored by third party developers.