Out comes the entire off-the-shelf Mini-ITX motherboard.

This Steam Box is equipped with two modules of Crucial Ballistix Sport 8 GB DDR3 (PC3 12800) RAM. At 16 GB total, it's the maximum this motherboard will support.

A nook in the motherboard cowling gives you access to the RAM before you get this deep. But they won't be easy to finagle out of their slots, even with only one clip apiece to secure them.

This motherboard includes DisplayPort, DVI, and HDMI ports, just in case you feel like using the integrated Intel HD Graphics 4600 instead of the GTX 780.

Valve was nice enough to discourage this with port covers.