Hi, the size of their proposed computer of 3.4x 2.1 inches already includes the Epiphany accelerator core that covers 16 to 64 cores. So within the size of 8.636 X 5.33 you get a performance of 16 x 700 Mhz and 64 x 700 Mhz that is 11.2 Ghz to 44.8 Ghz. So no need to stack them up like the Atx...
Well these guys have already proved it with a full fledged working prototype and all they need is some money to get the flow going. This idea is huge and this company could as well reshape the face of personal computer.
Some one posted this in another thread but here are his views
"Very cool!
Its weird, I was JUST reading a book where Feynman was giving a lecture in the late 70's about parallel low power processing in the future"