I'm not exactly an expert but here's a wild guess as to what the PS4's hardware will look like anyway:
CPU - 4x @ 3.5 GHz
GPU - 2 GB GDDR5 RAM
RAM - 2 GB DDR3
SSD - 32 GB (for OS)
HDD - 1 TB SATA @ 6 Gb/s
ODD - 12x Blu-Ray
I'd guess that in late 2014 this would cost about $450 to manufacture and assemble allowing Sony to price it at $400.







