Valve has released the specifications for their proposed steam machines, the ones that they are shipping out to people. They do say that people will be able to create their own machines for their own situations. Small form factor, super quite etc... The machines are fully upgradable and will be upgraded over time as new components are released.
Here are the specifications for Valve's 300 prototypes.
The 300 prototype units will ship with the following components:
GPU: some units with NVidia Titan, some GTX780, some GTX760, and some GTX660
CPU: some boxes with Intel i7-4770, some i5-4570, and some i3
RAM: 16GB DDR3-1600 (CPU), 3GB GDDR5 (GPU)
Storage: 1TB/8GB Hybrid SSHD
Power Supply: Internal 450w 80Plus Gold
Dimensions: approx. 12 x 12.4 x 2.9 in high
Check out the full announcement.



