8600K dropping voltage under load

[Vario]

Just set up this system and I am having problems getting any higher clock speeds than stock out of it. I used prime 95 as a quick load test to see how high it would go in temperatures and voltage. I set windows power option to high performance. Here is the stock results idle and load (P95):

I am running Windows 7 Pro. G Skill TridentZ 3200 CL14 16GB. Z370 Taichi and i5 8600K. I am using CPUID Hardware Monitor. Power supply is a SeaSonic 660 XP2 Platinum. Cooler is a Phanteks PHTC12DX with a Delta fan. The ram is not set to XMP right now.
Stock the CPU performs well as far as I can tell. Bios voltage of 1.088V. Maximum speed in Windows is 4.3Ghz. Under load in Prime95, max speed is 4.13GHz. Maximum temperature in Prime95 is 51*C. Max Vcore 1.120. Idle voltage ~0.6V. Load VID 1.265V.

I reset my bios to defaults. Then I tried the auto OC setting, the result is a bit strange. It sets the core to 4.1Ghz (no higher than before). VID requested under load is 1.265V.

Sitting in windows, my voltage is 1.264V. Seems that auto OC disables offset. When I run prime 95, the voltage drops to 1.184V. All 6 Core speed is 4.1Ghz. Temperature max is 52*C. When I stop prime 95, voltage rises back to ~1.264.

I tried manual overclock in Bios setting the all core speed to 44. Voltage to 1.280V in Bios. Same result, core voltage drops under load. Tried LLC Level 1. Core voltage is higher but it is still lower under load. Tried setting the power limits long and short and durations to the maximum values (rather stupendous level). Same result. Temperatures whole time are spot on low 50*C. Wattage of the package is only 83W, so its not actually pulling a whole lot.
The voltage also does not like to remain constant when I use a fixed value of 1.280V. It varies quite a bit between .68 to 1.280v. In the past, on my old 3770K when I set a fixed voltage it was a fixed value. It only varied maybe +/- .005V.

Any thoughts?

 

[erocker]

You'll probably have to set/change your LLC setting. I'm not sure how to go about it on Asrock boards tho.

 

[Vario]

I have tried LLC1 (which is max) and auto. Same thing, however the voltage is higher than before, it still drops substantially when I run it under load. It should stay about the same. The thing shouldn't be throttling. If it sits at hypothetically 1.25V and I run prime95 and it goes to 1.15V, then I stop Prime and it goes back to 1.25V, seems kind of odd.

 

[biffzinker]

Something to do with the new AVX offset setting in the uEFI for Coffeelake/Kabylake dropping the clockspeed, and voltage worth checking up on? You said your stress testing with Prime95 which uses AVX2.

 

[W1zzard]

What does Throttlestop's throttle reason window show?

 

[Vario]

I was reluctant to update the bios but I updated the board to version P1.30 from P1.10 and the voltage is now holding as it should. I will check the throttle stop if I experience further issue.

 

[Aquinus]

LLC isn't a bad thing. There are voltage spikes and drops when the CPU goes from idle to load and the other way around. LLC makes the spikes less painful for the CPU and the VRMs (but more for the CPU.) I would trust higher voltages with LLC doing its job than slightly lower voltages without it.

 

[Vario]

I think in this instance it was the bios. Things are now working as they should I think. I will update if I have further issue. So far 4.5ghz @ 1.2V, will keep boosting and see where I end up.

 

[Vayra86]

I believe for the Taichi the common idea is to put LLC at the LOWEST setting. The aggressive setting may very well cause these small spikes. Have seen it too on my board (much older, Z77).

In addition, before (!) and after changing LLC, download OCCT and run a stress test pre and post change, check the graph for CPU vCore. It can give you a much better idea of how its spiking.

EDIT: I see you updated BIOS. Nice. Still the above does apply

 

[cadaveca]

I believe for the Taichi the common idea is to put LLC at the LOWEST setting. The aggressive setting may very well cause these small spikes. Have seen it too on my board (much older, Z77).

1 is highest, 5 is lowest LLC on ASRock. He has it sorted though; BIOS needed update. Discord FTW.

 

[Vario]

I am running LLC 3 right now, seemed like a good place to start as it is in the middle. 1.232-1.264 Volt under load for 5 Ghz in Aida64 with temps maxing at 68, averaging about 60*C. Offset mode +40 with C states active and balanced power in windows.

Edit: also messing around with what I can achieve with stock voltages via overclock with negative offsets, and I am able to reach 4.7Ghz at 1.184v in Aida64 stability test with all C states and ram XMP. Max temp is only 60*C under full load with these settings. Pretty good processor I think.