Its in the Settings..
Governor ? Semaphore by Default use an optimized Ondemand Governor which stays longer on the 1GHz(or your selected Max frequency) so it consumes more power.
Did you used the Only 100mhz if GPU is inactive and/or Deep Idle ?
Live OC and/or You Changed the max step to 1,2/ 1,3 ?
All these things should be mentioned, if you use semaphore.. Same with Glitch(liveOC, Sleep Governor etc.)