Looking again at the specifications for Valve's own prototype for their Steam Machine one thing jumped out of the page at me - this powerful, fully specced gaming PC isn't even going to be 3-inches high. That's slimmer than the XBone, and there's a GTX Titan inside. I sat down with a ruler, a mini-ITX motherboard and a Titan to try and visualise the way the Steam Machine is likely to be laid out inside, and with a little imagination you can see what a lovely, sleek little device this could turn out to be.

Those Steam Machine specs in full…

The 300 prototype units will ship with the following components:

CPU: 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

I put together a few components to see if those slimline specs are doable, and they are. My main concern though is the cooling. I've checked out some impressive low profile coolers recently and Valve isn't using the overclockable K-series processors from Intel so I'm not too worried about the CPU. The graphics card is another matter. Ensuring this thing has adequate airflow to stop the card needing to spool up its fans to max, the instant you start gaming, is likely to be quite a challenge.

I'm also intrigued as to how loud this prototype is going to be. With small fans in the PSU, CPU cooler and graphics card - having to work pretty hard in all likelihood - it could end up being a rather noisy beast. It's all very well having a machine small enough to fit under your TV, but if it drowns out everything that's happening on-screen it's a bit of a worry.

Valve will have thought of these issues too, of course. It'll be interesting to see what they have in place to solve them. The fact that this is just the prototype has me very excited for the seriously small form factor chassis that are bound to be copycat-created once the inaugural Steam Machine is out of Valve's laboratory.

I'll be doing a lot more investigation into custom Steam boxes and small factor components shortly, so keep an eye on PCGamer.com for more soon.