How do I overclock?

[Woolleyvamp]

so I have an i7-8700K paired with an Asus Z370-I itx motherboard and I'm trying to overclock the CPU and since it's an itx system, I only want to OC to 4.2/4.5GHz.

My issue is that I just cannot get the CPU to stabilise and stay at a constant speed.

Can someone help?

 

[Radox-0]

For the two numbers you gave, there is no point in trying to overclock to 4.2 GHz, the 8700k has a all core boost of 4.3 GHz by default on all 6 cores, so manually setting 4.2 GHz will in effect be a downclock. 4.5 GHz is similarly not too hard to do as the 3 core boost of the 8700k is 4.5 GHz and you would be downclocking the 1 and 2 core boost of 4.6 GHz and 4.7 GHz. An easy trick to use with the 8700k on ASUS boards is to enable Multi-core Enhancement (MCE) in the BIOS and set all cores to sync. This will allow the CPU to run at 4.7 GHz on all 6 cores without needing to do anything else. In my experience using the same board and CPU, the board does a okay job in terms of voltages (not too excessive) so could be worthwhile going this route.

Now in regards to a constant speed? when do you see it fluctuate? Unless the CPU is being stressed on all of the cores, it will not stay and the boost clock speeds by default and downclock and upclock based on load which is a good thing. Now you can lock the CPU to the turbo / boost clock speeds by setting Windows Power Management to maximum performance all the time, but really no point.

 

[Woolleyvamp]

For the two numbers you gave, there is no point in trying to overclock to 4.2 GHz, the 8700k has a all core boost of 4.3 GHz by default on all 6 cores, so manually setting 4.2 GHz will in effect be a downclock. 4.5 GHz is similarly not too hard to do as the 3 core boost of the 8700k is 4.5 GHz and you would be downclocking the 1 and 2 core boost of 4.6 GHz and 4.7 GHz. An easy trick to use with the 8700k on ASUS boards is to enable Multi-core Enhancement (MCE) in the BIOS and set all cores to sync. This will allow the CPU to run at 4.7 GHz on all 6 cores without needing to do anything else. In my experience using the same board and CPU, the board does a okay job in terms of voltages (not too excessive) so could be worthwhile going this route.

Now in regards to a constant speed? when do you see it fluctuate? Unless the CPU is being stressed on all of the cores, it will not stay and the boost clock speeds by default and downclock and upclock based on load which is a good thing. Now you can lock the CPU to the turbo / boost clock speeds by setting Windows Power Management to maximum performance all the time, but really no point.

does this mean that when I sync all the cores to, for example, 45 I do not need to adjust any voltages or do i still need to do this?

with regards to the speeds, by using the performance tab on in the task manager, the CPU speed seems to fluctuate between 4.18 to 3.9GHz under minimal load (around 10 minuets after boot and nothing open except background processes). Would this be improved by increasing the core sync?

 

[Radox-0]

does this mean that when I sync all the cores to, for example, 45 I do not need to adjust any voltages or do i still need to do this?

You still need to play with the voltages. They will be set to auto by default so will try to pump in more voltage. However Auto voltages can be overzelous so its still a good idea to try and manually put in the voltages and only as much as you need. Second benefit of having more refined voltages rather then having BIOS overshoot is lower temps.

with regards to the speeds, by using the performance tab on in the task manager, the CPU speed seems to fluctuate between 4.18 to 3.9GHz under minimal load (around 10 minuets after boot and nothing open except background processes). Would this be improved by increasing the core sync?

Use something like HWINFO. That will show per core clock speed while Task manager does not. Similarly do not worry about the speed the 8700k hits under low / minimal load, its really only under a heavy load you care about or when its actually doing a task you want it to sit at the boost clock speed. The 8700k is a bit finicky I and others have found and aggressively ramps up and down in terms of clock speed with even idle / low loads which is a non-issue, recall being part of a thread on another site showing 8700k clock does just like to jump around: https://www.overclock.net/forum/5-intel-cpus/1670593-8700k-high-idle-core-clock-voltage.html

 

[Woolleyvamp]

You still need to play with the voltages. They will be set to auto by default so will try to pump in more voltage. However Auto voltages can be overzelous so its still a good idea to try and manually put in the voltages and only as much as you need. Second benefit of having more refined voltages rather then having BIOS overshoot is lower temps.



Use something like HWINFO. That will show per core clock speed while Task manager does not. Similarly do not worry about the speed the 8700k hits under low / minimal load, its really only under a heavy load you care about or when its actually doing a task you want it to sit at the boost clock speed. The 8700k is a bit finicky I and others have found and aggressively ramps up and down in terms of clock speed with even idle / low loads which is a non-issue, recall being part of a thread on another site showing 8700k clock does just like to jump around: https://www.overclock.net/forum/5-intel-cpus/1670593-8700k-high-idle-core-clock-voltage.html

thank you very much! I'll have another go in the bios tonight. Many thanks again.