Hm, I feel there is some miscommunication going on.
Lets not debate about the pros and cons between 7 and 10. That's already done all over the world after all.
A declining performance in a windows 7 install does not point towards the os in question. There is something else going on.
Then I like to point out that most of the responders here run a dual boot, at least I am, and writing this from windows 10.
I feel they are the same, at least in desktop mode, minus the graphical interface and some incompatibility issues.
Then all future software will still run fully on windows 7, for the afformentioned reason, minus ofcourse the DX12 games.
Ah yes, DX12. I recall installing DX1 and after that version 2. after that 2A ? Well, it's a long time ago so I could have it wrong in my memory. It promised a mind blowing experience and improvements. Alas, all ran the same, looked the same, had the same speed.
Then came DX3, which required you to have a DX3 compatible card. Bought one and enjoyed, eh, the same as before.
But ok. If one feels things run much better with windows 10, then sure, use it and enjoy it.
I use both and enjoy both.