If N5 or the digital hub is based on a totally custom cpu, it will probably be very powerful, however I highly doubt it would even be in the hundreds of GFLOPS range let alone TFLOPS. I'd say more than 50 but less than 150 GFLOPS. The GPU would be the real GFLOPS monster anyway. The reason for this is I think the conglomerate wants the cpu to be cheap to manufacture so that they can add other features without having to worry too much about additional costs. Therefore the cpu will not be huge like CELL. I'd say less than 200 million transistors.
Edit: Also because IMO the cpu in N5 will be fabbed using 0.09u...
Edit: Also because IMO the cpu in N5 will be fabbed using 0.09u...