Firstly- 100% GPU Usage. This means that your graphics card is being fully utilised for the game. Every resource that the GPU has is being used towards the game. It's nothing to worry about, rather something to be happy about.
If your only getting 60-80fps in games, there may be something throttling you.
What games are you playing? Framerates vary between games. For example, I get 120+ fps in R6S with my GTX 1060, but only 70-80fps in Far Cry 5 (both running at 1920x1080 on Ultra).
What resolution are you playing at? GTX 1060s perform best in games at 1920x1080.
Can you confirm there are no hardware or software that may be throttling your graphics card?
Are you sure you have tried changing graphical settings within games, then restarting the game to see if changes work?
If you have any more questions or concerns, leave a comment.
Hope this helped!
-Lachlan
EDIT: I agree with @pete_101, 8GB of RAM is quite low for today's standards and may be something that is throttling you.