Just out of curiosity, why would you want to disable the down throttle? Unless you are only using your PC for gaming/ext, why would you not want it to step down? I use my PC as much online as I do gaming so 0,988v to cruise the internet compared to 1.376v to play a game is clutch. The funny thing is that I can play the same games at max settings at 4.6g as I can at 5,0g with no in-game-detectable-differences.
All I am trying to say is... max out your PC for benching but if the difference is not detectable in everyday use, why wear your chips more than necessary?
I can run my ram at 2133MHz or 2400MHz at a difference of 0.150v for a difference of 46ns and 49ns. I cannot tell the difference between the two on an everyday aspect, My bottleneck is at internet provider lvl so the difference between 120 fps and 100 fps isn't even noticeable on use. Match you OC to your needs.