Well for the moment I stick with windows 7, as there are very few games out that use direct x 12 features.
Also if you only have a card that is capable of direct x 11 hardware implementation stick with windows 7 if you are currently using it.
Playing a game with direct x 11 on windows 7 vs windows 10 only gives you about an extra 2 fps if your lucky.
No doubt it will change when a lot of games start using the direct x 12 Api.
But then there is also Mantel, and Vulcan to consider as well, that may help with better or higher frame rates in games also.
Not just the fact you are running a graphics card on windows 10 Byron.
It`s too early to tell, to be honest the new Doom game a few weeks ago, ID released a Vulcan patch for the Vulcan Api.
To run the game, I would ask some one if that made a difference, or they got a frame rate increase, and what Os they were running it under windows 7 or windows 10.
Right now as much as direct x 12 and only windows 10 having support for it.
Where as Vulcan is supported in windows 7 and 8 as well as then it`s a good question to ask Byron.
Personally I don`t like windows 10, due to Microsoft not allowing the user to make his own choices on updates, and how much data windows 10 collects.