Max or safe CPU VID voltage for i7 9700k when overclocked.

Somnath Ghosh · December 18, 2019

Hey, I overclocked my i7 9700k with an air cooler at 4.7Ghz with a cpu vcore of 1.21v in the bios and with a LLC of mode 5 (using MSI MOBO), the one just below the flat line curve and when stress testing, I am hitting 72 degrees C max (after an hour of stress testing) and is able to maintain that speed all the time.

My main concern is that while stress testing, the cpu vcore of CPU-Z is showing 1.208v but in HWmonitor, the cpu vid voltages are maxing out to 1.29v and the cpu vcore apply mode is in Override mode in bios.

So is it okay? Or am I doing anything wrong or will this degrade my cpu lifespan or is it completely safe for daily use?

unclewebb · December 18, 2019

CPU-Z shows the actual voltage going to your CPU. Most motherboards allow you to control the voltage going to the CPU so they ignore the VID voltage signal. The reported VID voltage is a meaningless number. Ignore it. If you are not sure, use a multimeter and measure the voltage directly at the CPU socket. If you are only overclocking to 4.7 GHz, I would not bother.

Somnath Ghosh · December 18, 2019

46 minutes ago, unclewebb said:

CPU-Z shows the actual voltage going to your CPU. Most motherboards allow you to control the voltage going to the CPU so they ignore the VID voltage signal. The reported VID voltage is a meaningless number. Ignore it. If you are not sure, use a multimeter and measure the voltage directly at the CPU socket. If you are only overclocking to 4.7 GHz, I would not bother.

So you are saying that I don't have to worry at all and is pretty much good to go for the daily use?

Falkentyne · December 18, 2019

1 hour ago, Somnath Ghosh said:

Hey, I overclocked my i7 9700k with an air cooler at 4.7Ghz with a cpu vcore of 1.21v in the bios and with a LLC of mode 5 (using MSI MOBO), the one just below the flat line curve and when stress testing, I am hitting 72 degrees C max (after an hour of stress testing) and is able to maintain that speed all the time.

My main concern is that while stress testing, the cpu vcore of CPU-Z is showing 1.208v but in HWmonitor, the cpu vid voltages are maxing out to 1.29v and the cpu vcore apply mode is in Override mode in bios.

So is it okay? Or am I doing anything wrong or will this degrade my cpu lifespan or is it completely safe for daily use?

Just FYI, the MSI 'lines' are completely garbage and mean nothing.

They are based on the Super I/O sensor voltage reading, which is all kinds of inaccurate.

If your MSI board has VR VOUT access shown in HWinfo64 (usually with International rectifier or some Intersil VRM's), then this will show you the true voltage and true vdroop.

If not, then what you need to remember is this.

Mode 1=flat loadline (0 mOhms).

Mode 2 is usually between 80-85% reduced vdroop.

Mode 3 is (most likely) 75% reduced vdroop. This is equal to LLC: Turbo on Gigabyte boards and LLC6 on most Asus boards.

Mode 4 can be anywhere between 50% reduced vdroop to some random setting close to 50%. For example, Gigabyte boards "LLC High" is 50% reduced vdroop while Asus LLC5 seems to be about 40% reduced vdroop, which is a rather big jump from LLC6.

BTW Asrock's "level 1" loadline is not 0 mOhms. It's more like between 80%-90% reduced vdroop but not 0 mOhms (no vdroop).

Anyway, oscilloscope captures of loadline can be seen here.

https://elmorlabs.com/index.php/2019-09-05/vrm-load-line-visualized/

Here is a visual representation of certain LLC levels, which may not be on your actual board, but which shows the relationship between LLC and vdroop and output voltage.

https://www.overclock.net/forum/6-intel-motherboards/1638955-z370-z390-vrm-discussion-thread-398.html#post27860326

As you can see, a NEGATIVE vdroop (sustained voltage RISE under load compared to Bios setting) is simply not possible when using FIXED VOLTAGE modes. It is possible under offset/auto modes (when something called "AC Loadline" is combined with aggressive Loadline calibration), but that's because of the influence of AC Loadline, which changes operating voltages (along the AC circuit) that the VRM receives (before vdroop). AC Loadline and Loadline Calibration are *NOT* the same thing.

Transient spikes and dips are the result of load release/activate and capacitors charging and overshooting (or undershooting) their voltage mark. Only oscilloscope charts can show these.

By the way, before you run around thinking Mode 1 / LLC8 / LLC Ultra Extreme is actually good to use because of no vdroop, go back to Elmor's "LLC8" chart and then ask yourself why you shouldn't use LLC8/Mode 1.

Hint:
this person's post shows (using voltage measured via differential die-sense) that just switching from LLC5 to LLC6 required the *LOAD* voltage to be HIGHER to maintain stability.

https://www.overclock.net/forum/5-intel-cpus/1735616-9900ks-lottery-thread-30.html#post28242754

If this confuses you, go back to Elmor's oscilloscope graphs and compare LLC5 and LLC6 then it will begin to make sense.