Requesting feedback about overclock. 6850K @ 4200 (ASRock X99M Killer 3.1)

[paw4444]

I have spent a good amount of time to find the sweet spot for temperature / noise / performance.

After a lot of tests with Prime95 and IntelBurnTest I have these two options.

6850K @ 4200 MHz @ 1.287
I ran a lot of tests to find the lowest voltage for this speed. Prime95 (28.9) - 2 hours, x264 Stability Test (v2.06) - 4+ hours, IntelBurnTest (Standard - 75 runs and Very High - 10 runs) then multiple CPU benchmark tests.

6850K @ 4300 MHz @ 1.379
Prime95 - 3.25 Hours

I decided to stick with the 4200 because of the lower voltage and temps.
NH-D14 works great for cooling with low fan speeds. When rendering (Corona, Cinebench) temps stay below 70 degrees (room temp ~ 25). Idle CPU temp between 27 and 31.

I am asking for feedback and help on what more I could do to improve the overclock. Up to now I have restored the default BIOS values and have then tweaked only the most basic settings to get to a stable 4200 MHz.

Additionally I have applied the Adaptive Voltage to let the CPU voltage drop when the CPU is idle.
In HWMonitor I only see the VID value go down (From 1.287 to 0.770). Is this correct or does VCore also need to go down?

Any feedback greatly appreciated!!


I am attaching photos of the settings in BIOS. Motherboard is ASRock X99M Killer 3.1:
01_OC_Tweaker_CPU

02_OC_Tweaker_CPU

03_OC_Tweaker_DRAM

04_OC_Tweaker_FIVR

05_OC_Tweaker_Voltage

06_Advanced_CPU_Configuration

 

[scuzzycard]

Now that you found a sweet spot for the core, I would try overclocking the cache a bit. You won't get much of an increase in performance compared to what you get from overclocking the core, but free performance is free performance.

 

[paw4444]

Thanks for the suggestion! Looks like I have completely overlooked this.
Is there some kind of ratio related to the core? How much approximately I could expect to get it to?

Once I overclock the cache, I just will run CPU stress tests again and see where it crashes and then go back a bit or more. Correct?

 

[scuzzycard]

The setting is "CPU Cache Ratio" right below CPU Ratio. I would start at 35 (3500MHz) and work your way up to 42. Then, yes, stress test again. Use Blend instead of Small FFT in Prime.

 

[paw4444]

I started at 35 (3500) could boot and IntelBurnTest (25 Standard) succeeded. 3600 would boot but fail the same test. 3700 would not boot. I plan to run Prime95 after IBT test is passed.

Then I saw under FIVR Configuration (Image above) there is CPU Cache Voltage Mode. Currently on Auto.

I will start increasing the CPU Cache Voltage and work my way up to 4200 and try to find the sweet spot.
Having Vcore Voltage at 1.287 what would be a similar level of overclock for the cache in terms of voltage (for the CPU Cache Voltage)?

 

[scuzzycard]

You'll probably end up at 1.20 to 1.28 for the cache.

 

[paw4444]

I tried setting it with adaptive voltage although anything higher than 3600 wouldn't boot. I would prefer not to have a fixed voltage, although I read somewhere that adaptive for the cache might have some issue with the CPU.

In the end I just left it on Auto and did a few tests. The max stable on Auto is 3400 so I left it at that.

Thanks for the help!

 

[scuzzycard]

No problem, there's nothing wrong with keeping it conservative. Enjoy it!