Of all the Steam Machines detailed at GDC 2015, Zotac's seems the most interesting. The SN970 isn't ready for release, but that's not just because Valve is targeting a November launch for their living room hardware platform: Zotac's Steam Machine also includes unreleased hardware.
The SN970 will feature a yet-to-be-released Intel sixth-generation 'Skylake' CPU, specifically a quad-core Core i5 model. Skylake, with a new architecture built on a 14nm process, is set to be launched near the middle of 2015, around the same time (though probably slightly later than) Intel will launch Broadwell's performance SKUs.
As the SN970 will be launched in November alongside other Steam Machines, there should be no issues in delivering a Skylake model, provided Intel doesn't delay its release.
Other hardware in Zotac's Steam Machine includes an Nvidia GeForce GTX 970M, which Zotac claims will occupy around half of the system's total 100 W TDP. Storage will be provided through a 64 GB M.2 SSD and a 1 TB 2.5-inch hard drive, while wireless connectivity will include dual-band Wi-Fi AC.
The system will support up to four displays thanks to four HDMI 2.0 outputs on the back panel, as well as mini-DisplayPort, two Ethernet ports, two USB 2.0 ports and four USB 3.0. As the internal components are too powerful, the Steam Machine will include active cooling via two fans.
Zotac is keeping quiet on what the SN970 will cost, although the inclusion of SteamOS rather than Windows will cut the down the overall price. Judging by the hardware inside, we wouldn't be surprised to see it retail for twice the price of a current-generation console when it hits the market at the end of the year.