i7 6700K Stuck at max clock speed

[Ethan-7]

OS: Windows 10 Pro 64bit
CPU: i7 6700K
Mobo: MSI Z170A-G45 Gaming
GPU: RTX 2080

Noticed lag spikes while gaming, checked temps to see that they are fine (CPU is 30-40) but noticed the clock speed is stuck at 4000MHz even after closing everything. Load is anywhere from 3% - 20% with just firefox open currently but still sitting at max clock speed. This just randomly started.

I've checked windows power settings, I'm on balanced with min speed at 5% and max at 100%.
I don't and have never had any overclocking settings on in the BIOS or through software. I'm at a loss. Any help is appreciated.

 

[shknawe]

That is your base frequency, 4.0. And 4.20 is your max frequency (without oc it) for that cpu so there is nothing wrong with your cpu.
And to help with lag spikes you may want to change it to high performance. The lag could be your cpu spinning up from 5 percent to whatever power it needs.

 

[Ethan-7]

I'm fairly certain my max speed is 4.0. Should the frequency not be dropping down when I am idle?

 

[Countgreen]

The CPU should throttle down when not in use. If you go into your BIOS make sure that Intel C state is enabled.

 

[Ethan-7]

Intel C state was on auto, I changed it to enabled. I also enabled C1E as I read was a solution to this issue in another thread- now my CPU clock speed is jumping every 2 seconds or so to 3600 for a moment and then back up to 4000, as if it's attempting to throttle down but something is overriding it.

 

[Dugimodo]

Is there also a setting for intel speed step?
When I had a 6700K it would drop down much lower than yours is when idle, and that's even with an overclock or MCE enabled.
I think 4 Ghz is the all core turbo speed and 4.2 is the single core turbo, with MCE enabled it becomes 4.2 all core which is technically a slight overclock.

 

[Ethan-7]

There is an option for intel speed step which is enabled...

I think I just discovered a bigger issue though- one with my mobo. The Z170A has a "slow mode" switch that has something to do with liquid cooling or something. It's in the physical off position on the board but it just randomly started registering as being on, which is throttling my CPU down to 800mhz. Now I'm locked at a low clock speed.

I just flicked the switch on and back off. It went back to normal (as in stuck at 3600-4000mhz) for about 5 minutes and then randomly started registering as being switched on again.

Update: I read about the issue with the slow mode switch in other threads and found that you can disable Intel Adaptive Thermal Monitoring in BIOS to stop the throttling, and this appears to be a common problem with this mobo. But now I am back to my initial problem- still sitting at 4000mhz while idle.