I normally get 99% with my Titan Xps. What's your TDP look like?
You could try increasing target power/temp and see if that helps. If that doesn't make a difference you may need to do what I had to do when I had my AMD cards. I had an odd clock/usage issue with folding at home after a driver update. I ended up having to remove my over clocking software and the drivers, then run DDU and install drivers.
I don't know if that's an issue that has come up for Nvidia cards, I haven't run into it yet at least.
If you do get DDU you may want to check before you download the new version. I heard a rumour that the newest possibly has malware in it. Saw it on Reddit earlier but haven't looked into it more.