Can't seem to properly OC i7-7700k, help?

[spiffles]

Howdy folks, 

I'm using an Asrock Fatality Z270 Gaming I7 board and a i7-7700k processor. Just picked up the amazing Noctua NH D15 cooler, which is able to keep this CPU at under 85 degrees after 10 minutes of Prime95 testing, with the peak being 86 degrees on two cores. The voltage is 1.350v. Of course stuff like Cinebench is much cooler, in the vein of 70 degrees more like.

The only problem is, that I can't seem to get a stable clock speed, since disabling Turbo Boost will not have my BIOS overclock the processor anything above the stock 4.2 GHZ. So even now, I'm at 4.7 GHZ boosting occasionally to 5.0 GHZ, even though the CPU ratio is 50 and the cache ratio is 47. Curiously, while stress testing the frequency never goes above 4.7 actually (both in Prime95 and CinebenchR20). All diagnostic software indicates a 4,7 GHZ clock speed under load. 

Why doesn't my CPU want to run consistently at 5 GHZ, or at the very least reach that frequency under load? Why is it jumping between 4.7 and 5.0, but mostly staying at 4.7 - all the while producing as much heat as proper 5.0 would? Why is the ratio variable rather than staying constant?

 

[Jurrunio]

because you have AVX offset set to 3. Set it to 0 instead

[spiffles]

3 minutes ago, Jurrunio said:

because you have AVX offset set to 3. Set it to 0 instead

Aye. figured it out in the meantime but thanks anyway! 

So what's this AVX offset good for? What are AVX and SSE workloads mand why is it desirable to do AVX workloads at lower clock speeds than SSE workloads?

[Jurrunio]

Just now, spiffles said:

So what's this AVX offset good for? What are AVX and SSE workloads mand why is it desirable to do AVX workloads at lower clock speeds than SSE workloads?

because Intel CPUs run extra hot and less stable in AVX workloads. Uisng AVX offset means running the CPU faster for other types of work.

[spiffles]

Alright, cheers!