Asus, Lenovo, Samsung and Toshiba will be authorized to sell ARM-based tablets running the Windows RT OS, Microsoft confirmed. Microsoft's next OS will support both x86 and ARM-based processors. NVIDIA, Qualcomm and Texas Instruments will design System-on-Chips that will power the RT tablets.

In a blog post today Mike Angiulo, the vice president of Microsoft's ecosystem and planning team spell out some specification ranges for the new hardware.

The upcoming devices will include both tablets and laptops, and run the gamut of form factors. "Some of our Windows RT PCs come with full keyboard and touchpad solutions, whether removable/dockable or a traditional clamshell," Angiulo said.

According to Angiulo, some of the new Windows RT devices will be up to 11 percent thinner than Apple's iPad, and weigh 20 percent less.

Screens sizes will range from 10.1 to 11.6 inches, said Angiulo.

Angiulo did not disclose the price range for the Windows RT devices from the four OEMs.

Microsoft will launch Windows 8 October 26 with the first compatible tablets set to follow. It's own tablet, the "Surface", will come in both Windows 8 and Windows RT versions.