As Windows 8 and its accompanying devices launch on Oct. 26, you’ll want to make sure you know the differences between the various flavors of Windows 8 before purchasing a device or upgrade pack. Microsoft announced months ago that it will have three consumer versions of its upcoming operating system: Windows 8, Windows 8 Pro, and Windows RT. While there are some small variations between Windows 8 and Windows 8 Pro, the biggest differences lie between those two — which have a full-featured Start Screen and desktop environments — and Windows RT, which is a mobile environment that runs only Windows Store apps and built-in software.

These aren’t cosmetic differences; Windows 8 and Windows RT look nearly identical, with the new tile-based Start Screen UI and the available desktop mode. But the under-the-hood differences have a significant impact on how you can use your devices — Windows RT is a tablet- and mobile-focused OS, while Windows 8 is a full-featured PC operating system. They look the same but behave entirely differently, which, obviously, leaves room for confusion.

Microsoft says that it’s working to ensure its store employees know the differences between Windows RT and Windows 8, but as The Verge found, that’s going to take some time. Even with Surface RT pre-orders open, many Microsoft employees were unable to explain what Windows RT could and could not do.

In the interest of helping them — and you — here’s a breakdown.







Windows 8

Windows RT Release Date

October 26

October 26 Price

Windows 8 and Windows 8 Pro will be available to purchase as standalone upgrades in retail stores and online. The physical upgrade pack for Windows 8 Pro is already available for pre-order for $70. Microsoft has said that users will be able to upgrade to Windows 8 Pro online on Oct. 26 for $40. People who purchased a Windows 7 device between June 2, 2012 and Jan. 3, 2013 will be able to upgrade to Windows 8 Pro for $15. Microsoft has not yet announced pricing for basic Windows 8.

Windows RT is technically priceless, since you will not be able to purchase an upgrade package for Windows RT. It will only be available built into specific devices, like Surface RT and other offerings from Microsoft’s OEM partners. Windows RT devices are expected to cost much less than Windows 8 devices. Hardware

Windows 8 will only run on x86 devices, powered by Intel or AMD chips.

Windows RT will only run on ARM-powered devices. ARM chips tout better battery life and lower prices. Battery Life

Upcoming Windows 8 devices tend to have an estimated battery life between 6 and 8 hours.

Windows RT devices promise longer battery life than most Windows 8 devices. Microsoft says that Surface RT will have “all-day” battery life, or between 8 and 13 hours. Dell claims that its upcoming XPS 10 RT tablet can get up to 20 hours of battery life. Interface

Full-featured Start Screen and desktop mode.

At first look, Windows RT has the same interface as Windows 8. But while Windows RT has a desktop mode, it is far from full-featured. In fact, you won’t be able to run any third-party software on the desktop in Windows RT, not even different web browsers like Firefox or Chrome. (See more below.) Software Support

Windows 8 will be able to run all software from the Windows Store and any third-party programs that you may have used in earlier versions of Windows.

Windows RT only supports apps from the Windows Store and its built-in version of Office 2013. This means you won’t be able to download any software from the web that is made to run in the desktop environment. No third-party browsers, no third-party games, no third-party anything. Everything you run on Windows RT has to be approved by Microsoft and available in the Windows Store. Currently the Windows Store has around 5,000 apps, more than 90 percent of which are compatible with Windows RT. It’s not a terrible number of apps, but there are some key missing players like Spotify and Facebook. Windows RT also does not port Windows Media Player, though it does come with other build-in media players like Xbox Music. Business Use

While Windows 8 is a drastic shift from previous versions of Windows, it does support the tools business users need. Windows 8 Pro offers a Remote Desktop server, Active Directory domain support, Encrypting File System, Hyper-V, BitLocker and more.

Windows RT is not necessarily a business-friendly platform. Because it is so closed off to third-party software, users will have to depend on the built-in Microsoft apps to do work. The built-in RT version of Office 2013 does not come with common business software like Outlook. But at least you will get Word, Powerpoint and Excel. A Windows RT device like Surface RT could potentially be a good additional business tool, but if you want a full-featured enterprise platform, you’ll need to go with Windows 8. Who Should Buy

You should buy Windows 8 if you want to have a full-featured operating operating system with an actually useful desktop mode. If you depend on third-party software, then stick to Windows 8 and Windows 8 Pro. The system is built for notebooks, desktop PCs, and convertible devices.

If you want a tablet or mobile converible that functions like the iPad, then a Windows RT device is a good fit. The Surface RT, for example, is enough for somebody who wants basic productivity tools like Office alongside the touch- and mobile-friendly environment. Just remember that Windows RT is limited to apps in the Windows Store, which is not very robust yet.

(Images: Lenovo (left), Microsoft (right))