F5F Stay Refreshed Power Users Overclocking Question I7 8700k OC vcore and core clocks fluctuation

Question I7 8700k OC vcore and core clocks fluctuation

Question I7 8700k OC vcore and core clocks fluctuation

T
TiPlaysFTW
Member
Find
53
08-31-2025, 06:22 AM
#1
Hello,
I’m setting up my first PC and this is my first attempt at overclocking. I’ve read and watched numerous guides, so I’m familiar with the basics.

My current specs are:
- Intel i7 8700K delidded
- MSI Z370 Gaming pro Carbon
- Corsair Vengeance LPX 3000Mhz CL15
- Shreddy Fuma Rev. b
- Bitfenix Whisper M 650w
- Silverstone RL 06 GP

These are the BIOS overclock settings with the latest update. If not listed, they’re at the default:
- CPU Ratio: 51 (all cores)
- CPU Ratio mode: Dynamic
- CPU Ratio Offset When Running AVX: 0
- Enhanced Turbo: Disabled (tried disabling but it didn’t help)
- 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 currently running AIDA 64 stress test (about 50 minutes in, focusing on CPU, FPU, cache, and system memory). I’m using HWMonitor to monitor everything.

CPU temperature averages around 70°C, with a peak of 82°C. One core reaches up to 74°C, but the fans aren’t spinning at full speed—likely around 70%.

This is where the issues start:
- The CPU Vcore keeps changing constantly between 1.385 and 1.4, reaching a maximum of 1.416 and a minimum of 1.352. I set it to 1.38V in BIOS!
- Core clocks aren’t stable at 5.1GHz; some cores drop to 4.8GHz and then jump back up to 5.1, while the other two or three drop to 4.8GHz before returning to 5GHz. It’s impossible to maintain all six at 5.1GHz together.
- When I’m not running the stress test, they settle at 5.1GHz.

Why isn’t my Vcore matching what I set in BIOS? Why do both Vcore and core clocks swing so much?

Thanks for your help!
Reply
Reply
T
TiPlaysFTW
08-31-2025, 06:22 AM #1

Hello,
I’m setting up my first PC and this is my first attempt at overclocking. I’ve read and watched numerous guides, so I’m familiar with the basics.

My current specs are:
- Intel i7 8700K delidded
- MSI Z370 Gaming pro Carbon
- Corsair Vengeance LPX 3000Mhz CL15
- Shreddy Fuma Rev. b
- Bitfenix Whisper M 650w
- Silverstone RL 06 GP

These are the BIOS overclock settings with the latest update. If not listed, they’re at the default:
- CPU Ratio: 51 (all cores)
- CPU Ratio mode: Dynamic
- CPU Ratio Offset When Running AVX: 0
- Enhanced Turbo: Disabled (tried disabling but it didn’t help)
- 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 currently running AIDA 64 stress test (about 50 minutes in, focusing on CPU, FPU, cache, and system memory). I’m using HWMonitor to monitor everything.

CPU temperature averages around 70°C, with a peak of 82°C. One core reaches up to 74°C, but the fans aren’t spinning at full speed—likely around 70%.

This is where the issues start:
- The CPU Vcore keeps changing constantly between 1.385 and 1.4, reaching a maximum of 1.416 and a minimum of 1.352. I set it to 1.38V in BIOS!
- Core clocks aren’t stable at 5.1GHz; some cores drop to 4.8GHz and then jump back up to 5.1, while the other two or three drop to 4.8GHz before returning to 5GHz. It’s impossible to maintain all six at 5.1GHz together.
- When I’m not running the stress test, they settle at 5.1GHz.

Why isn’t my Vcore matching what I set in BIOS? Why do both Vcore and core clocks swing so much?

Thanks for your help!

Reply
Reply
S
SpacinetiX
Junior Member
Find
46
08-31-2025, 06:22 AM
#2
-CPU Core/ GT Voltage Mode: Adaptive
There could be a voltage offset, either from this setting or a separate configuration in your BIOS that enables it to vary +/- on the voltage.
-CPU Ratio mode: Dynamic
The CPU ratio mode is also set to dynamic, permitting it to adjust to what it requires.
In your power options, you have defined minimum and maximum processor speeds in your Windows settings, which also permits the CPU ratio to decrease when not needed.
You might want to explore these options and see if they assist. I favor the fluctuations; I don’t like my chip running at full strength or voltage constantly.
Reply
Reply
S
SpacinetiX
08-31-2025, 06:22 AM #2

-CPU Core/ GT Voltage Mode: Adaptive
There could be a voltage offset, either from this setting or a separate configuration in your BIOS that enables it to vary +/- on the voltage.
-CPU Ratio mode: Dynamic
The CPU ratio mode is also set to dynamic, permitting it to adjust to what it requires.
In your power options, you have defined minimum and maximum processor speeds in your Windows settings, which also permits the CPU ratio to decrease when not needed.
You might want to explore these options and see if they assist. I favor the fluctuations; I don’t like my chip running at full strength or voltage constantly.

Reply
Reply