I was having the same problem on the same chip.
Mine is in an asus pro wifi ac board. Here's the part picker list, complete with fap-worthy setup pics: partpicker.com/b/b9BPxr
I have a turbo profile I usually run at 4.8ghz, and away mode supposedly brings me to 3.7ghz. Problem is, task manager and logitech arx control always showed cpu spinning @ .8ghz aka 800mhz sometimes 801mhz.
I did everything I could, disabling intel speedstep in the bios, setting windows power plan up for max performance, etc etc, and still had the same issue.
The problem with this, is certain games/programs won't even run if they sense low cpu cycles.
I can't get siege beta to run
So I was literally about to uninstall asus cpu turbo tool and see if that helped, when I realized it had a setting called "configured max cpu power" enabled. In the description it tells me that it uses power supply reduction to cpu to conserve power. I disabled that, which forces a restart, and now task manager reads proper cpu cycling.
And now rainbow 6 siege beta runs great!
Hope this post helped someone.
Have a great day, and hail gaben. -DeputyDanTV