Re-install 8.1 on new hardware and upgrade to 10?

[Borealis]

Hi all.

Apologies if this has been asked a billion times before!

I have an OEM DVD copy of 8.1, just like I have an OEM DVD version of 7.

I've just bought an X99 board/CPU/RAM combo and will be replacing my Z97 system. If I upgrade the system to 10 first, will I then be able to change the hardware or is 10 going to get locked to my motherboard?

Alternatively I can re-install 8.1 on the new hardware and then upgrade. I take it that 8.1 will behave like 7 and just let me re-install?

This isn't my primary system, so if it's down while I have to faff around, I don't mind!

 

[Borealis]

Thought that would be the case. I don't have an unused key unfortunately...

Is this something that only applies to Win 8.1 and 10?

With Win 7 I've definitely re-used an OEM key before without issues, even when changing motherboard.

Edit: Just to clarify, it's not a pre-built 8.1 OEM key. I think it's a system builder DVD. If I end up paying for another licence, so be it.