How old or low spec have you tried running Windows 10 on?
I have a Panasonic CF-Y4 laptop, which is a Centrino system - a Pentium M single core at 1.6 GHz, and I have 1 GB of total RAM installed. Bought this way back in 2003 or something.
It came with Windows XP, which ran pretty well on it. I didn't upgrade it to Vista or Win7 as I didn't see any major change. Then when Win8 came out, with a low intro price for upgrade, I took the plunge... That didn't work as well as I hoped - it ran, but very sluggishly.
When Win10 came out I didn't bother to put it on this hardware, even tho it was free, thinking if Win8 was sluggish here would Win10 even work?
Boy was I wrong. I just found out the free upgrade was still available as of now
(for certain uses, which you have to declare
) so I was like why not. I upgraded it to Win10 and now it runs just as well as XP! Honestly I wouldn't believe it if I wasn't typing this on this 14 yr old laptop right now.
Now, I still have a Pentium 3 tower from 1999 with 512mb of RAM and a legit XP license... nah... mmm... hmm