I’ve seen a few blog comments that ask specifically about minimum resolution, for example on Designing the Start screen in October 2011, @wolf asked:
“A better idea would force all developers to make sure all Metro app [are designed for] a minimal screen size of 800x600. Limiting Metro apps to only 1024x768 will cut out all netbook users as well as hurt the Windows App Store."
We chose a minimum screen resolution of 1024x768 in order to make it as simple as possible for developers to create great apps that work on all the different screens that are available now and in the future. A minimum resolution provides a necessary starting place for developers, who can use it as a baseline to ensure that all of the navigation, controls, and content fit on screen. As we worked on different design layouts for apps, we found that the higher the minimum resolution, the richer and more tailored the app could be. We wanted developers to be able to tailor and refine their layouts to make use of every available pixel on 1024x768, without having to compromise the layout for a smaller resolution.
We chose 1024x768 as a minimum for Metro style apps for three reasons.
It is large enough to support the rich and beautiful layouts that we expect to see with Metro style apps. Lower resolutions, like 800x600 for example, require simpler more basic layouts with less content.
Websites are typically designed for 1024x768 as the minimum (or only) resolution, and web developers are used to targeting this resolution.
Looking at the data about devices in the marketplace today, we see that only 1.2% of active Windows 7 users have screens with a resolution of less than 1024x768. When designing a new platform that supports the devices of today and tomorrow (with undoubtedly higher resolutions) we optimized for the majority of today’s screens (i.e. 98.8%) without sacrificing the experience and complicating the developer story for legacy screens. In addition, the runrate of new PCs with screen sizes of 1024x600 and 1280x720 has dramatically fallen and, to the best of our knowledge, almost no new mainstream PCs are being manufactured with this resolution. We are aware of purpose-built machines that run at lower resolutions, which are built for specialized desktop apps as well. While many run virtual machines, VMs can easily support 1024x768 even though many default to lower resolution.