Microsoft is on track to release to manufacturing (RTM) all Windows 8 versions by April 2012. The plan is to RTM Windows 8 for x86, Windows 8 for ARM/SoC (system on a chip), and Windows 8 Server all at the same time, according to ZDNet.
Microsoft's plan is deliver a single Windows 8 beta build (not a pre-beta or preview, according to the rumor) around the time of its upcoming Build conference. Microsoft is hoping to convince Windows, Windows Azure, Windows Phone, and Web developers to attend the event in Anaheim, California between September 13, 2011 and September 16, 2011.
Following the beta, Microsoft will deliver a Release Candidate (RC) build of Windows 8 sometime in January 2012. The final released build will be the RTM. This would mean only two public test builds, which is what we got for Windows 7.
April 2012 seems very early for the RTM. We've previously heard summer 2012 for the RTM target, but that could be what Microsoft is hoping for as a last resort.
If the April 2012 RTM target turns out to be reality, Microsoft and its OEMs will definitely be able to deliver Windows 8 PCs in time for next year's back to school and holiday seasons.
Although a rumor suggests that Windows 8 will arrive on January 7, 2013, we expect that the operating system will ship in time for the 2012 holiday season. In fact, Microsoft CEO Steve Ballmer has said Windows 8 is coming in 2012, but Microsoft quickly claimed this was a misstatement.