When the new SDK launches, devs can recompile their apps to run in 64-bit on ARM-based PCs. 32-bit performance has been found to be generally acceptable with current Snapdragon 835-powered systems, but it remains to be seen how they will fare with 64-bit apps. These machines typically run Windows 10 S, but free upgrades to Windows 10 Pro are offered through 2019.
The ARM 64 SDK will reportedly be offered for Store apps and their desktop counterparts. It is still relatively early in the game, but so far Windows on ARM machines haven't exactly burned up the sales charts. Part of the challenge in getting machines such as this adopted by end-users is that they are expensive compared to some full notebooks.
The HP Envy x2 2-in-1 Snapdragon-powered notebook went up for