The entire tech world would think that Microsoft doesn't have to support those new retina displays, but that would sound like suicide to the OS. The latest and "greatest" Windows will support resolutions up to 2560 x 1440 on screens as small as 10.1 inches. That's a pretty impressive 291 pixels per inch. Of course, it's not quite as simple as it sounds. While in an ideal world, every UI element would be resolution independent, that's simply not the case and the infrastructure isn't there to support it. Instead graphical elements, including text, must be scaled to fill the available pixels. Microsoft's scheme will use 100 percent for standard density displays, 140 for HD and 180 for quad-XGA panels. Thankfully, the company was smart enough to include support for SVG files as UI elements, meaning that density and resolution independent future is at least one step closer.
Source: Building Windows 8