Microsoft and its partners have been busy talking about Windows 8 and the various Intel-based devices it will run on, but the ARM-based Windows RT is still somewhat of an unknown quantity. We know a bit about the most high-profile Windows RT PC, the Microsoft Surface, as well as a few other devices, but OEMs have been hesitant to provide more concrete details about such things as battery life. This, however, is beginning to change.

In a new post on the Building Windows 8 blog, Mike Angiulo, the vice president of Microsoft’s Ecosystem and Planning team, revealed a few average stats for Windows RT PCs. Microsoft has put a few upcoming Windows RT devices – running unfinished firmware, mind you – through a number of tests and determined that the average device should support approximately 8-13 hours of HD video playback and 320-409 hours of power while on connected standby. In other words, you’ll be able to leave your device in an “always on and always connected” state, which keeps all of your data up-to-date, for just over 17 days. These numbers might change slightly based on your hardware configuration, of course, but it’s not too shabby.

Microsoft is working with ASUS, Dell, Lenovo, Samsung, and other manufacturers to deliver a number of ARM-based Windows RT devices in various form-factors like tablets and laptops. So far, these devices have had an average weight of 520-120g, length of 263-298mm, width of 168.5-204mm, and height of 8.35-15.6mm. As a result, the devices can be smaller than the iPad or much larger, depending on OEM/customer preference.

Finally, Windows RT’s UI animations will run at a buttery-smooth 60fps – what you’d expect from a game like Call of Duty – and all devices will support a number of common touchpad gestures, where applicable. This includes standard cursor manipulation, click/right-click, horizontal and vertical scrolling, pinch-and-zoom, and swiping in from the sides or top to invoke the charms.

[Building Windows 8]