Manually set it to 50% then and see what that does for temps. Understand that the cpu does not care what it's temp is, anything underneath throttle temps is all the same to the cpu. It's only the bios fan curves that will change that, unless you use something like SpeedFan where you can make your own auto curves to replace the factory. So since 76 is under throttle temp, that's what you'll get, no difference between that and 47 to the cpu. You'll only lower temps physically by changing to a higher capacity/effective heatsink which'll overpower the ability of the cpu to put out heat, so gaming only reaches mid 50's - 60's at that same 25% fan duty.