Update (February 9) : It turns out Microsoft misstated how much storage is available to users on both the 64 GB and 128 GB models of the Surface Pro.he Verge (citing a Microsoft spokesperson) reported on January 29 that t he amount of usable storage on both the 64 GB and 128 GB models will be substantially smaller than many may expect. The 64 GB Surface Pro will have 23 GB of free storage out of the box, and the 128 model, 83 GB of free storage.