Overclocking i7-6850K on MSI X99a Workstation

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mstuder

Commendable
Jan 29, 2017
3
0
1,510
Dear all,

I'm trying to overclock an i7-6850K on an 'MSI X99A Workstation' motherboard to 4.2 GHz.

System Details
CPU: i7-6850K
Motherboard: MSI X99A Workstation
RAM: Corsair Vengeance LPX DDR4 32GB (4 x 8GB) - 3333 MHz
Cooling: Corsair Hydro Series H100i v2
OS: Manjaro Linux

Overclocking Details
Base clock: 100 MHz
Multiplier: 42
CPU Ratio Mode: Dynamic - i.e. both EIST (Enhanced Intel Speed Step) and Turbo Boost enabled
XMP: enabled - using DDR4-3200
Hyperthreading: enabled
Long Duration Power Limit: max
Short Duration Power Limit: max
CPU Vdroop Offset Control: +50%

I don't seem to manage to get the cores up to 4.2 GHz. When running mprime (Prime95 on Linux) across 12 threads, I only get 2 threads up to 4 GHz (with a 4.2 GHz overclock), all other threads are running at 3.8 GHz.

I tried OCing both in Override and Offset mode but without any luck. I tried disabling several combinations of

  • Intel C-State and C1E
    EIST
    Internal VR OVP OCP Protection
    Internal VR Efficiency Management
    Intel Adaptive Thermal Monitor

but without any luck. In general, I would like to achieve a friendly overclock, leaving as many of the above enabled to reduce power consumption when the system is not under heavy load.

Any idea of what could be limiting the CPU to run at 4.2 GHz across all cores?

I'm using cat /proc/cpuinfo | grep "MHz" and the I-Nex utility to check core speed.

Thanks & Best regards,
Martin

 
Solution
Mikel_4
You didn't miss anything, you've disengaged motherboard's brake so it depend on how your CPU compute, again the point of CPU stressing is to see how fast the cores at, you'll end up running in circle trying to get that as you wanted or contact . To confirm the throttling issue you can use http://www.ekwb.com/shop/ek-tim-indigo-xtreme-intel-2011-3.html. After that go to BIOS and disable P-State, + 0.5Vcore offset, tried this and 6900K 8 cores went to 4.4GHz on windows task manager, sadly I got BSOD rendering with Blender Cycle.
You've set multiplier to 42X and got 4.0GHz ? I'm not familiar with Linux, also don't want to judge the reading accuracy, never in my experience setting multiplier gone wrong on Windows, and I told you before to...
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Mikel_4

Mikel_4

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Oct 15, 2016
712
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2,660

    ■ Its synthetic apps, if you seriously need 6 cores at their highest MHz try Corona Render, Handbrake, or other CPU intensive programs, you can consult hardcore coder to tweak your program on CPU raw speed and cores count max up. So what you plan to do with 6 cores on 4.2GHz anyway?
    ■ Tried Cinema4D, still couldn't get 6900K cores at certain speed evenly, and the result of stock to 4GHz was mare 2-3 seconds finish different.
    ■ I figured that was apps dependent or Intel's power limitation or BIOS incapability, I rendered hundreds 3D images (to became couple second animation scene) and had gone to GPU render (ditched Xeon core and turn to CUDA instead), for a 10-30 seconds completion different, times hundred scenes, I've had more times for design or leisure.
Cooling VS Heat

  • ■ When electric energy is being used on CPU, it convert to heat (as a waste leftover), heat is spreading toward heatsink>air or liquid then hot temperature disperse (by air pressure) or absorb (by coolant)> air or coolant transfer cooler temperature. By chemical or physical the coolant have higher heat transfer coefficient than air. For long max CPU usage then you should consider CPU liquid cooler, for gaming air will suffice.
    ■ For Broadwell E CPUs SKU, Intel was focusing on core count + high clock speed + proprietary tech, for us users we just have to figure out what cooling options we implement and OC preset that will be stable on our system.
    ■ You can also look for other part optimization, use low timing (CAS, RAS...) and highest DDR4 speed preset + use M.2 stick (samsung 950 PRO or intel SSD 750 PCIE/U.2), the fast RAM will help overall system processing and fast SSD will help read/write operation.
 
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M

mstuder

Commendable
Jan 29, 2017
3
0
1,510
Thank you for your answer.

mprime, as far as I understand, should very well max out the CPU's (virtual) cores. So I'm expecting all 12 (virtual) cores to run at nearly 4.2 GHz (with some small variations over time). I don't understand why I only see two (virtual) cores running at 4 GHz (not even 4.2 GHz) and the rest at 3.8 GHz. Something must be throttling. As I mentioned, I tried disabling various power management and protection options but to no avail. What else could there be that I missed?

By the way, I ran handbrake and got the same results: 2 cores running at 4 GHz, the rest at 3.8 GHz.



 
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Mikel_4

Mikel_4

Respectable
Oct 15, 2016
712
0
2,660
You didn't miss anything, you've disengaged motherboard's brake so it depend on how your CPU compute, again the point of CPU stressing is to see how fast the cores at, you'll end up running in circle trying to get that as you wanted or contact . To confirm the throttling issue you can use http://www.ekwb.com/shop/ek-tim-indigo-xtreme-intel-2011-3.html. After that go to BIOS and disable P-State, + 0.5Vcore offset, tried this and 6900K 8 cores went to 4.4GHz on windows task manager, sadly I got BSOD rendering with Blender Cycle.
You've set multiplier to 42X and got 4.0GHz ? I'm not familiar with Linux, also don't want to judge the reading accuracy, never in my experience setting multiplier gone wrong on Windows, and I told you before to consult expert coder. Too bad I couldn't be more assisting.
 
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