Hot Chips: Xbone Silicon (5b transistors, 363mm2, 8GB Flash, 1.31TFlops, 204GB/s peak BW)

[Adinnieken]

Basically, he's saying that the Xbox One is capable of 5TFlops. It's performance is actually on par with a high-end PC, and will be beyond 2015. The SoC in the Xbox One is a W2W design, with the Move processors on the base layer, the APU on another layer, and the ESRAM on top. There is apparently some significant importance to being layered vs. being laid out on one wafer.

EDIT: Corrected the TeraFlop info.

Conversely the PS4 is 3.2TF