The Verge had the opportunity to test Valve's Steam Machines at the company's Bellevue, Washington headquarters. You can read the site's experience over here, they write Valve's steel and aluminum chassis measures just 12" on a side and is 2.9" tall, making it a little bit bigger than an Xbox 360, yet capable of packing high-end CPUs and NVIDIA's GeForce GTX Titan. Interestingly, Valve designed the case so each key component can exhaust air to the outside in order to prevent heat buildup inside the case.
The secret is actually quite simple, it turns out: Valve designed the case so the parts can breathe individually. The CPU blows air out the top, the power supply out the side, and the graphics card exhaust out back, and none share any airspace within the case.
That might sound like common sense, but it’s remarkably hard to find a case that does so while still making it easy to drop components in. Here, the key component responsible for dividing those three zones is a simple plastic shroud which unscrews in a jiffy. The box we touched was already surprisingly cool and quiet, but Valve's still tweaking the design: we saw Valve printing a couple of the shrouds as we walked through its rapid prototyping lab.