I heard some people saying that Nvidia GPU's can go up to 120C without overheating.
Anyways I decided to try clean it out a bit.
It didn't helped though.
When I turned on my PC temp were going up to 80C and then fan increased its speed
and got temp down to 66C.
Right now its 72.When I was about to post my fan increased its speed again and brought temp down to 63.
Now it is slowly rising.
EDIT: I think it did helped because my GPU is at ~85C when I'm running Gmod on max settings.