I'm in the process of installing Windows 10 Pro Full Version (using Win 8 Pro code I reserved previously) on a new PC.
 
However, I'm undecided as to which SSDs to use , currently doing test install, off the net,  on an ADATA 240 GB SSD.
 
Another SSD - Samsung EVO 120 GB shall be arriving in a few days time.
 
What happens if I activates Windows 10, installed with the ADATA SSD, then later decide I would like to switch to Samsung EVO as an OS drive (same PC) ?
 
Thanks in advance!
 
Note : first time using SSD ... oh boy booting to Windows is fassssst!!!

I have already replaced several HDDs to SSDs (all EVO or EVO Pro) using Samsung utility. So far there was no problems, neither with copy nor with activation. I can not give direct link, but I remember MS mentioned that replacing disk does not influence the activation.

Generally you are not going to have a problem if all you change is your boot drive. You likely will have a problem if you replace your motherboard--technically speaking that is a new computer. If you are using a Win 8 product key code to install Win 10 then you are not installing a "full version" but an update from Win 8. There is a full version available for sale that has its own product key, and will allow you to transfer the OS to a new computer in the future. There is some ambiguity involved, but the majority opinion seems to be that an upgrade using a Win 8 license is not going to be transferrable to a new computer. 
http://www.howtogeek.com/226510/how-to-use-your-free-windows-10-license-after-changing-your-pc%E2%80%99s-hardware/
 

Thanks for the replies! Upgrade / activation with digital entitlement - that pretty much clears up the intention of the free upgrade to Windows 10 to be none transferable. But it's still a good deal as Windows 10 performance for audio will be better ! ..hopefully 

You can do a direct "clean" install without doing an upgrade first if you want. 
 
Here is the instructions from the Win 10 forums.
http://www.tenforums.com/tutorials/23354-clean-install-windows-10-directly-without-having-upgrade-first.html
 
 

fireberd
You can do a direct "clean" install without doing an upgrade first if you want. 
 
Here is the instructions from the Win 10 forums.
http://www.tenforums.com/tutorials/23354-clean-install-windows-10-directly-without-having-upgrade-first.html
 
 

Thanks fireberd, I'll install Windows 10 directly.

There is a MUCH easier way to do the clean install, that does not even require that you have ever had the previous version installed anywhere, and certainly does not involve getting a GenuineTicket.XML file from another installation. If you use the current Win10 iso downloaded using the media creation tool, then simply enter the product key for a qualifying version of Win7 or Win 8 when first asked for a product key during the installation, your new Win10 installation will activate automatically on connection to the internet. The product key you enter from Win 7 or Win 8 will determine if you get a pro or home version of Win10 installed, and you should download the iso version for 64 or 32 bit installation of your choice. 

With regards to the actual license for Windows 10: If you upgrade, it is locked to that computer and Microsoft has chosen to define "computer" as your motherboard. Replace that, you need a new license. Keep it, and you should be able to change out anything else you like as often as you like. If you do a reinstall, ignore the key entry field in the installer, it'll activate when it connects to the Internet the first time.
 
For the retail copy, you can move it system to system but if you do it too much it'll stop working and you'll have to call MS. Usually an easy process just requires more time on the phone than you should have to spend. It generally tracks systems by a constellation of hardware, and can deal with changes without reactivation so long as not too many things change in too short a time. So if you swap a drive, no problem. Next month swap a GPU, no problem. However swap your board, CPU, HDD, GPU and audio card all at once, it'll probably want to reactivate.