It should be closer to 100mh/s, definitely over 90mh/s. My 3070Ti manages 81mh/s out of the box.
What OS are you running on and what drivers are you running. How are your temps and OC settings?
I am running win10 Pro with driver 472.12.
How are your temps ----> The mem temp is 90, OC setting is default as I am new on Nvidia GPU as all my rigs are running AMD