Ever since the availability of the Surface RT from Microsoft there has been a demand for an x86-emulator for ARM chips. Although the newer versions of the Surface now run on an Intel x64 platform, the first and second generation Surface tablets run on an ARM architecture. As a consequence these tablets can only use the special apps from the Windows Store. Even though Windows RT, at first glance, looks very similar to Windows 10, it is impossible to run 'standard' Windows applications on Windows RT. This limits its potential utility considerably, of course.
Perhaps a change is coming. There are rumors going around that the Redstone 3 update for Windows 10 may include an x86-x64-to-ARM emulation implementation. The biggest obstacle, the performance limitation that accompanies emulation, has largely been eliminated by the continuing development and much increased speed of ARM processors. In addition, the ARM architecture is not all that different from the x86 architecture; at least less than the Cell and Itanium architectures.
Still, will have to wait a while. The Redstone 3 update has been planned for the fall of 2017...
More information: www.zdnet.com/article/microsofts-x86-on-arm64-emulation-a-windows-10-redstone-3-fall-2017-deliverable/