I did a test which shows that you can boot from a Windows 10 installation with different hardware.
I have connected my old Hard drive to a Lenovo Laptop (Intel Core i3 CPU , my damaged PC has an Intel Core i5 CPU). The System boots. After some seconds a screen with "Getting Devices ready" appears, and after 10 minutes the system was restarted and booted normally. After this I installed new device drivers, and everything seems to be working well. Of course, the activation problem remains.
I'm not sure whether it will work just as well going from an Intel to an AMD based system or vice versa.
Additionally, I've found a claim that : "... Unlike Windows 7. Windows 8/10 is very forgiving. If you take out the HD and put in another MB, Windows will boot and recognize the missing drivers and will attempt to install them ..."
Source: http://www.tenforums.com/drivers-hardware/16276-moving-current-hdd-win10-another-pc-different-motherboard.html
Update:
Second test , I've put my HDD to a Dell laptop , so a totally different Motherboard. The same behavior : The system boot , after I see a "Getting Devices Ready" screen , and after 7-8 minutes Windows is open. I have installed new drivers and everything works fine.