Microsoft is getting ready to ship a version of its Surface tablet, the Surface Pro, which features the full Windows 8 operating system installed on the tablet. The device comes in two models, a 128GB and a 64GB. Microsoft even makes a note on the specs of the Surface Pro that formatted storage capacity will be less but doesn't mention exactly how much less. Want to know the truth?

Microsoft's Surface tablets have turned out to be a double-edged sword for the company. The devices were initially well received until they actually went on sale and customers began figuring out that the tablets aren't exactly what many hoped they would be. The Surface with Windows RT ships with an operating system that only allows apps to be installed from the Windows Store, not apps that run on the desktop version of Windows. Microsoft highly touts that the Surface RT ships with Microsoft Office but customers soon learned that Microsoft forgot to include Outlook with the pre-installed office suite.

The Surface Pro on the other hand ships with a full version of the Windows 8 operating system, allowing you to run apps that run on the desktop version of Windows. Consumers who purchase the Surface Pro will be happy to learn that Outlook will run on the Surface Pro. However, you'll just need to buy Microsoft Office since the tablet does not ship with a version of Office installed.

Now comes word of an even bigger letdown facing the Surface Pro before it goes on sale. Microsoft is shipping two different models of the Surface Pro. One configuration comes with 64GB of internal storage and the other comes with 128GB of internal storage. It is widely known that there is always a difference in the actual formatted storage capacity when it comes to the advertised spec. Microsoft even makes a note on the Surface Pro's Web site letting consumers know that "System software uses significant storage space; your storage capacity will be less". Unfortunately they forgot (or was it intentional?) to list how much less it really is.

Since people began inquiring on what the actual usable space would be Microsoft has had to address the issue and it might make people think twice about actually purchasing a Surface Pro. Here's their official statement:

"The 128 GB version of Surface Pro has 83 GB of free storage out of the box. The 64GB version of Surface Pro has 23GB of free storage out of the box. Of course, Surface Pro has a USB 3.0 port for connectivity with almost limitless storage options, including external hard drives and USB flash drives. Surface also comes pre-loaded with SkyDrive, allowing you to store up to 7GB of content in the cloud for free. The device also includes a microSDXC card slot that lets you store up to 64GB of additional content to your device. Customers can also free up additional storage space by creating a backup bootable USB and deleting the recovery partition."

As I said before, it is widely known and accepted that actual storage space is always less than the reported size, but the difference in the Surface Pro's case is substantial. If you compare Apple's just announced 128GB fourth-generation iPad with the 128GB Surface Pro, the iPad ships with 122GB of usable storage for $799 (WiFi model), while Microsoft's Surface Pro ships with 83GB of usable storage for $999 (Microsoft does not offer a cellular model). That means that Windows 8 and the pre-installed software are taking up a whopping 45GB of space on the 128GB model.

Does the Surface Pro still look like a winner for Microsoft??