Fatal1ty Z270 Gaming-ITX - UEFI problem?

The only thing I can think of is Speed Step, C States enabled or not using the high performance power plan within Windows.

arturk wrote: Does anyone know why when I use any of automatic oc profiles located in "Load optimized CPU OC setting" clocks are dropping down to 4.1 - 4.2 GHz during multi core prime95 stress test?? When I'm running exactly the same test in one or two threads I'm observing right frequency (for example 4.7GHz). When I am not using "Load optimized CPU OC setting" option and selecting everything manually, frequency of my CPU is as expected. If is select 48 core multiplier I have 4.8 GHz during prime95. I've checked every UEFI option and I am not able to find setting reletad to this core frequency drops.... Even if I select OC profile and then manually override every setting to default still clocks are dropping down during high load. Notice that 4.1 is lower then stock! Is there some "fake magic" behind this automating OC profiles?? Some hidden setting? Or maybe I'm missing something? Matherboard: Fatal1ty Z270 Gaming-ITX/ac Bios: 2.20 - latest CPU: I7 7700K COOLING: water RAM: 2x8 GSkill Trident Z 3200 CL14 (memory settings are not connected to this issue) VIDEO: GTX970

arturk wrote: I disabled both - speedstep and C states and made test: manual settings - clock is 4.8 GHz all the time (as expected!) 4.8GHz OC profile - also locked on 4.8 but under prime95 load after few seconds frequency is dropping to 4.1GHz and fluctuating a little bit. So... thanks for replay, but I think source of the problem is somewhere else. Guessing this is BIOS bug  / error (since manual OC seems to be ok)

No chance is that caused by C States or SpeedStep, the behavior is unrelated to those options.

I have the Z270 Gaming K6, and found the option (and difference in settings) between the auto OC profile and manually over clocking.

Either you missed it, or your board does not have this option available for configuration. In my board's UEFI, it is in the CPU Configuration screen, from the OC Tweaker screen.

AVX Ratio Offset. When manual over clocking, this option remains on the default Auto setting, equivalent to zero. This is the setting when my board's 4.7GHz Auto OC profile is selected:




AVX instructions have been a problem in stress testing with Intel processors since the X99/Haswell HEDT processors. They increase CPU temperature and power draw, so are also a stress on the CPU VRMs.

This option set like this is done for safety reasons for those that tend to use built in OC profiles.

Are you lowering the voltages on the auto profiles? They tend to use a lot more voltage than needed. What you are experiencing sounds like thermal throttling to me, either on the CPU or the VRMs. The fact that manually dialed in settings do not exhibit the same behavior further makes me think this is the case. 

I run test on different CPU sample. And situation is exactly the same. When OC profile is selected there is frequency drop during heavy load. No matter what I choose in BIOS. Having this option disabled and every other settings set to exactly same value - magic - clocks are rock stable!