Low gpu usage

[s26rech]

I have a 980ti sli configuration and it always worked fine. 1/2 months ago almost any game started heavy stuttering due to low gpus usage, in fact the cards always run low usage but never 99% ( 60/70/80/50 etc ), this is very annoying and it also happens in easy games ( rocket league doesn't go above 200 fps and it keeps stuttering ) and even using a single gpu in any of the pcie slots. I already tried to check temps, install differents drivers, overclocking cpu and ram, kboost, pcie power management, formatting to a fresh os, memtest and checking cpu and ram usage. I think it could be due to a bios/os setting because I already tried everything hardware and driver side but it could be wrong of course.
Any help?

i7 6700k ( stock due to high temps but even clocking it to 4.6ghz makes no effect )
Z170 Pro Gaming
Corsair H100i
Evga P1000
WD Black
Samsung 850 Pro Evo
2x4gb Kingston Savage 2133mhz
Sli 980ti g1 gaming
Haf X
W10 ( last build )

[PigWithAMustache]

Did you reboot your PC? Because it doesn't seem like you did that since you didn't say you did.

[Godlygamer23]

How high are the CPU temperatures? Your temperatures shouldn't be that high necessarily with an H100i.

[Mira Yurizaki]

Did you also try disabling SLI or trying with one video card or the other?

[s26rech]

11 hours ago, PigWithAMustache said:

Did you reboot your PC? Because it doesn't seem like you did that since you didn't say you did.

Well I got this problem 2 months ago, so yes lol

[s26rech]

11 hours ago, Godlygamer23 said:

How high are the CPU temperatures? Your temperatures shouldn't be that high necessarily with an H100i.

Probably I got a really unlucky 6700k because I always got around 70/75 degrees full load

[s26rech]

11 hours ago, M.Yurizaki said:

Did you also try disabling SLI or trying with one video card or the other?

Tried any gpu in any slot