I7 8700k OC vcore and core clocks fluctuation

[Leyo]

Hello,

I made my first pc and so it's the first time for me overclocking, I read and watched many guides so I know the basics.

Specs:

-I7 8700K delidded

-MSI Z370 Gaming pro Carbon

-Corsair Vengeance LPX 3000Mhz CL15

-Schythe Fuma Rev. b

-Bitfenix whisper M 650w

-Silverstone RL 06 GP



These are my overclock settings in bios with the latest update, if not here they are at default setting:

-CPU Ratio: 51 (all cores)

-CPU Ratio mode: Dynamic

-CPU Ratio Offset When Running AVX: 0

-Enchanced Turbo: Disabled (was enabled and I tried Disabled but didn't solve my problem)

-XMP: Enabled

-CPU Loadline Calibration Control: Mode 4

-CPU Core/ GT Voltage Mode: Adaptive

-CPU Voltages control: 1.38V

-FCLK Frequency: 1000Mhz



-Windows power plan: High performance



I'm running AIDA 64 stress test (as I'm writing this post, 50 minutes elapsed) on CPU, FPU, cache, system memory.

I'm using HWMonitor to control everything.



CPU temp is 70 C on average with the highest spike at 82 C but one of the cores max is 74C (my fans are not even at max, probably around 70%).



HERE COMES THE PROBLEMS!

-CPU vcore fluctuates constantly between 1.385 to 1.4, with max at 1.416 and min at 1.352 (I set 1.38V in bios!!!)

-Core Clocks aren't all stable at 5.1Ghz, some of them, in rotation (not always the same cores) drop to 4.8Ghz and then go back up to 5.1, then other 2/3 cores drop to 4.8, then they all drop to 5Ghz.

They can't keep all 6 5.1Ghz together, but when I'm not running the stresst test they all sit at 5.1.



So why isn't my vcore at what I set in bios and why vcore and Core Clocks fluctuate so much?



Thanks for the help!

 

[EarthDog]

-CPU vcore fluctuates constantly between 1.385 to 1.4, with max at 1.416 and min at 1.352 (I set 1.38V in bios!!!)

Normal variations... consider lowering LLC if you want it to be exact.

-Core Clocks aren't all stable at 5.1Ghz, some of them, in rotation (not always the same cores) drop to 4.8Ghz and then go back up to 5.1, then other 2/3 cores drop to 4.8, then they all drop to 5Ghz.

Power savings? Your core ratio mode is set to dynamic.......makes sense.

 

[Leyo]

Normal variations... consider lowering LLC if you want it to be exact.

Power savings? Your core ratio mode is set to dynamic.......makes sense.

So is it normal that it fluctuates a bit in dynamic?

I'm using dynamic because I don't want my cpu to be at constant 1.38V even when Idle

 

[wingman99]

Those fluctuations are all normal. I use dynamic and adaptive core voltage also.