i7 6700k Boost Not Working?


May 3, 2015
So I've had my 6700k for a while now and haven't overclocked properly yet as I want to get a better cooler first, and I figured the default 4ghz base and 4.2ghz turbo would be enough.
Now I don't know that much about Intel turbo boost and I always figured mine was working fine as it said just over 4200Mhz in RealTemp.

But recently I was using CPU-Z and saw that it wasn't going over 4000Mhz. I tried running Prime95 and this still stayed at 4000Mhz with the multiplier never increasing to 42 even though it says it can.

Temperatures are all fine and there is no issue there, with no throttling or anything.
I have come to the conclusion that RealTemp shows the maximum clock speed rather than the current one the CPU is running at.
I also noticed that the buss speed fluctuates while the multiplier always stays at 40x.
I tried disabling Intel Turbo boost in the BIOS and the results stayed the same as to when it was enabled. I was wondering if there was a setting I was missing in BIOS that is disabling the boosting of the multiplier? Or if everything is fine and how it should be?
Again, I am new to PC building and so if I got anything wrong or messed up, I appologise.
I have a MSI Z170-A PRO motherboard and a Hyper 212 EVO CPU Cooler.
Any help appreciated, thanks.
the turbo boost doesn't keep the clockspeed at a set speed it adapts to the workload you place on it. so if you are sufing the web you may only see a clockspeed of 2 orghz while if you start watching a video or play a graphically intensive game then you will start to see the clcokspeed go over the stock speed

but heat can play an issue too but i am using the stock cooler on my I7 7700 and have seen it reach the turbo speeds
It won't Turbo Boost with P95. Turbo Boost increases the clock rate in increments of 3 Core, 2 Core and 1 Core use. So it will only hit 4.2Ghz when the tasks it is working on can be done with one core only. This is managed automatically by the system.

I suppose if you want to test. You can go in the BIOS and disable all cores except for one. Then watch that one core hit 4.2Ghz.

When you overclock. Turn off Turbo Boost. Lock in your safe VCore and and stable clock rate at a safe temp. Then if you want to fiddle with Turbo Boost. You can see what speeds you can get with single/dual core turbo boost frequencies. While still maintaining safe temps and VCore.

Use OCCT to test temps and stability. After version 26.6 Prime 95 is no longer good for stress testing. As it makes use of AVX. Which will focus on your FPU and create artificially high temps.

I suppose you could use Prime 95 and OCCT. OCCT to test stability and Prime 95 to test the thermal limits.