Testing performance improvements by increasing clock speeds on the i7-6850K within the MSI X99a Workstation setup
Testing performance improvements by increasing clock speeds on the i7-6850K within the MSI X99a Workstation setup
I'm attempting to push an i7-6850K to 4.2 GHz on an MSI X99A Workstation motherboard.
System specifics
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 settings
Base clock: 100 MHz
Multiplier: 42
CPU Ratio Mode: Dynamic – both EIST and Turbo Boost active
XMP: enabled – using DDR4-3200
Hyperthreading: enabled
Long duration power limit: max
Short duration power limit: max
CPU Vdroop Offset Control: +50%
I haven’t been able to reach the cores at 4.2 GHz. When executing mprime (Prime95 on Linux) with 12 threads, only two threads hit 4 GHz (with a 4.2 GHz overclock), while the rest operate at 3.8 GHz.
I experimented with OC in both Override and Offset modes, but nothing worked. I also tried muting various Intel C-State and C1E settings, as well as disabling certain VR OVP and efficiency controls.
In general, I’m hoping to get a more comfortable overclock, keeping many features enabled to save power when the system isn’t under heavy use.
Any suggestions on what might be restricting the CPU from reaching 4.2 GHz across all cores?
I’ve checked
cat /proc/cpuinfo | grep "MHz"
and used the I-Nex tool for core speed analysis.
Best regards,
Martin
You didn't miss anything, you've turned off the motherboard's brake so it depends on how your CPU computes. The goal is to observe CPU stress by checking how quickly the cores operate. To verify throttling problems, visit the provided link. Proceed to BIOS and disable P-State, +0.5Vcore offset. After trying this, the 6900K with 8 cores reached 4.4GHz in Windows Task Manager, but I encountered a BSOD while running Blender Cycle. You set the multiplier to 42X and achieved 4.0GHz? I’m not familiar with Linux, and I don’t want to judge your reading accuracy—this has happened before on Windows, and I warned you earlier...
■ If you really need six cores at their top MHz, consider using Corona Render, Handbrake, or other demanding CPU programs. Consulting a hardcore coder can help adjust your setup for maximum CPU performance and core usage. What are your plans with six cores on a 4.2GHz processor?
■ Attempting Cinema4D didn’t yield consistent results at 6900K cores at certain speeds, and the stock version at 4GHz took 2-3 seconds to finish tasks.
■ It seems app compatibility or Intel’s power limits or BIOS restrictions might be involved. I rendered hundreds of 3D images, which took a couple of seconds for animation scenes, switching to GPU rendering for faster completion across hundreds of scenes. This has given me more time for design or leisure activities.
■ Heat management is crucial when using electricity on the CPU. Heat travels through the heatsink, air, or liquid, then dissipates via pressure or absorption by coolant. Coolants generally have a higher heat transfer rate than air. For extended CPU use, a liquid cooler is recommended; otherwise, standard air cooling should suffice.
■ For Broadwell E CPUs, Intel emphasized core count, high clock speeds, and proprietary technology. For users, the focus should be on selecting appropriate cooling solutions and optimizing BIOS/OC settings for stability.
■ You might also explore other component optimizations: use low timing (CAS, RAS), set the highest DDR4 speed, and consider using a M.2 SSD like Samsung 950 PRO or Intel SSD 750 PCIe/U.2. Fast RAM and a high-speed SSD will enhance overall system performance and speed.
I believe it's correct that the CPU should utilize its virtual cores fully. I anticipate all 12 virtual cores operating around 4.2 GHz, although I notice some fluctuations. Instead of seeing all cores at 4 GHz, I only observe two running at 4 GHz and the rest at 3.8 GHz. There must be something limiting performance. As discussed, I attempted to disable various power management and protection settings, but without success. Could there be another factor I overlooked?
Additionally, my tests with Handbrake confirmed the same pattern: only two cores at 4 GHz, with the remainder at 3.8 GHz.
Mikel_4 suggested that for demanding applications like Corona Render or Handbrake, you might need to push the CPU to its maximum MHz and consult a hardcore coder to adjust settings for optimal core usage. It’s unclear whether your current plan aligns with this approach.
He also mentioned trying Cinema4D, which didn’t yield the desired 6 cores at peak speeds, and experienced inconsistent completion times when switching to GPU rendering. He recommended consulting experts for CPU raw speed and core adjustments.
Regarding cooling, he explained that heat generated by the CPU dissipates through the heatsink or liquid, spreading to the surrounding air or coolant, which then transfers heat away more efficiently than air alone. For extended CPU use, a liquid cooler is advisable; otherwise, standard air cooling should suffice.
He noted that for Broadwell E CPUs, Intel prioritized core count, high clock speeds, and proprietary technology. Users should focus on selecting appropriate cooling solutions and optimizing BIOS/OC settings.
Lastly, he advised considering other hardware improvements: using low-timing instructions (like CAS or RAS), setting the highest DDR4 speed, opting for a M.2 SSD like Samsung 950 PRO or Intel SSD 750 PCIE/U.2, and ensuring fast RAM along with a high-performance SSD for overall system efficiency.
You didn't miss anything, you've turned off the motherboard's brake so it depends on how your CPU is computing. The goal of CPU stressing is to check how quickly the cores operate, and you'll end up stuck trying to reach that speed or the target. To verify the throttling problem, you can visit http://www.ekwb.com/shop/ek-tim-indigo-x...011-3.html. Then go to BIOS and disable P-State, +0.5Vcore offset. After trying this, the 6900K with 8 cores reached 4.4GHz in Windows Task Manager, but I encountered a BSOD while running Blender Cycle. You set the multiplier to 42X and got 4.0GHz? I'm not familiar with Linux, and I don't want to judge your reading accuracy. In my experience, adjusting the multiplier often goes wrong on Windows, so I always recommend consulting an expert coder. It's a shame I couldn't help further.