Windows 8 is on track to be released to computer makers the first week of August, and it will be generally available to end users at the end of October, the company announced this morning — giving the first official release timeline for the most significant overhaul of the company’s flagship product since Windows 95.

That’s a nearly three-month gap between RTM, as it’s known, and general availability.

Announcing the dates this morning at the company’s Worldwide Partner Conference in Toronto, Windows marketing and finance chief Tami Reller said the end-of-October timeframe will mark not just the first Windows 8 PCs but also the ability to upgrades to Windows 8 on existing computers.

It takes a while to test and deploy Windows on new machines, but why not sooner for the upgrade version? The company is relying heavily on downloads for Windows 8 upgrades, but releasing Windows 8 as an upgrade first would risk stealing some of the momentum from new Windows 8 computers from the company’s hardware partners.

The situation illustrates the company’s ongoing reliance on new computers as a distribution channel, responsible for the majority of Windows sales.

Microsoft has already stepped on the toes of PC makers with plans to release its Surface tablet computer, its first Microsoft-branded computer, competing with its partners’ Windows machines.

Microsoft CEO Steve Ballmer addressed that situation during his remarks at the conference, saying the importance of third-party Windows PC makers “will not diminish.” He said Microsoft may sell a few million Surface computers over the next year, but he noted that the overall market is projected to be about 375 million Windows PCs sold over the same time frame.

PreviouslyWindows 8 for $40: Will this convince you to upgrade?

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