What's your tdp settings. #2 need more power to give a boost.
Tried 100-110% with MSI 1080 Ti Sea Hawk X. ~1.8-2GHz core clock, -502 MHz GDDR5X. Used --cuda-schedule auto and without. What other parameters are there? On Nvidia 382.33, can't upgrade drivers atm cause this is the most stable for me. CPU time is 99%!
Try the latest driver. 384.94