I have been asking this question for some time now without a viable answer.
When I was convinced to buy this item, it came with a promise of 64bit emulator being very soon to follow, however this is now eight months later and still no idea how long we will have to wait.
I know that the emulator is currently available on the insider program, but all indicators are that its even more buggy than the somewhat limited 32bit emulator.
I'm surprised that Microsoft have not resolved the issues with this device as it would seem that they intend to peruse ARM technology in many future devices.
If the current state of play continues it could spell out disaster for this platform.
I have to say that there have been many updates for the pro x and it has improved over time, however many bugs and issues still remain and customer support for the pro x is at best very poor with the staff having little knowledge of the technical issues found on a daily basis.
Customer services have so far bricked the device on three occasions requiring hours of reloading and total loss of all data and without resolving the original problem (don't let them reset your device or set up phantom accounts) this doesn't work and creates more problems.
I have to say that given the choice again this device would not be on my shopping list.
The recent updates have made improvements and the device is now more stable than it was but without 64bit bug free emulator its very limited, Great looks and feel but don't judge the book by its cover,
If you intend to use only store apps and basic 32bit programs for surfing and emailing all is good, but for any serious use it fails badly at present, which is truly a shame as the device has great potential but is poorly supported from my own personal experience.
At present its only a little above windows other failed ARM devices using RT which of course is no longer supported.