Windows 10 gaming performance problem

Hi everyone,

Since I updated my computer to Windows 10, I can't play games as I used in the past with Windows 8.1
It is a little weird because Windows 10 performance overall is very very good. But when it comes to playing games, lag spikers are common and I can't play games at the same graphics detail level as I used with Windows 8.1

I have read a LOT of threads about possible solutions. Some claims that more RAM is needed. Some others that it may be related to graphics card drivers suitability to this operating system. I am inclined to the last option.
I have an MSI 60 2PC Apache. Some relevant specs:

Intel Core i7 4720HQ @ 2.60GHz
8,00GB Single-Channel DDR3 @ 798MHz (11-11-11-28)
NVIDIA GeForce GTX 850M

For example, I used to play Dead By Daylight at the high-level graphic detail in Windows 8.1. According to its requirements, I should run it without any problem. In Windows 8.1 it worked like charm. But when I say "like charm" I really mean it. Now I have to set graphics details to LOW if I want to make it playable. It is not something like "oh, yeah, it's a bit slower". Not at all, the game performance really sucks and it really impresses me how much gaming quality has been decreased.