Well, it looks like all those Metro app updates aren’t the only way in which Microsoft will improve Windows 8 between RTM (release to manufacturing) and GA (general availability): The firm revealed today that it will deliver a cumulative update for Windows 8 that amounts to a post-RTM service pack.

When I told you that Microsoft would update Windows 8 much more rapidly than with previous Windows versions, I didn’t realize it would be this fast.

“We are releasing a set of improvements to Windows 8 in broad areas of performance, power management and battery efficiency, media playback, and compatibility,” Microsoft’s Steven Sinofsky revealed in a post to the Building Windows 8 Blog. “These improvements are available starting today via Windows Update.”

Windows 8, mind you, isn’t available until October 26.

Sinofsky explains that the heightened release schedule isn’t all that different from how things were done in the past. With previous Windows versions, Microsoft would develop certain updates for their PC maker partners between the RTM of Windows and general availability, and that these updates would ship broadly to all customers only when the first service pack was released. With Windows 8, Microsoft has updated its internal processes to allow these updates to ship broadly right way, not just before the first service pack, but before Windows 8 is even released to the public.

According to the knowledge base article covering the update—officially known as Windows 8 and Windows Server 2012 General Availability Cumulative Update—Microsoft is making the following improvements to what it calls Windows 8 fundamentals:

- Increased power efficiency to extend battery life

- Performance improvements in Windows 8 applications and Start screen

- Improved audio and video playback in many scenarios

- Improved application and driver compatibility with Windows 8

“We think this new pace of delivering high quality updates to Windows will be a welcome enhancement for all of our customers,” Sinofsky concludes in his post. Indeed: “This new pace” sees Microsoft delivering a service pack-class update to Windows 8 just two months after RTM. If we can expect this pace continually going forward, Windows 8 will be significantly different at this time next year. Then again, that’s pretty much what I’d been told to expect.