Sharp voltage drop under load (i7-13700k, ASRock Z790)

[djesteban]

Hi,

I'm using an ASRock Z790 Steel Legend motherboard with an i7-13700k CPU.

I'm experiencing a significant voltage drop (Vdrop or Vdroop?) when the CPU is under load.

At idle, the voltage stays around 1.32V, and the core speed is around 4.2GHz. However, when I run a CPU-intensive task (like an x265 encode), the voltage drops to about 1.05-1.10V, and the clock speed decreases to 3.8-3.9GHz.

I've tried adjusting a few BIOS settings without success:

• Disabled/enabled XMP—no effect.
• Enabled/disabled OC mode in Voltage Configurations—no effect.
• Changed LLC (Load-Line Calibration) from Level 3 (default) to Level 2, then Level 1—this had no noticeable effect, which was surprising as I expected it to address the issue (See manual page 49).

The drop seems to occur a few seconds after the CPU load starts, around when temps hit 70-100°C. After the voltage drops, temps stabilize at 65-70°C. When I stop the encode, the voltage and core speeds return to normal.

Is there a way to maintain a higher voltage under load, maybe around 1.2-1.25V? I understand this might raise temps, but with current temps at 65°C, I’d be comfortable running up to 80-85°C.

I'm pretty n00b when it comes to this stuff, so please, if you need more information, don't hesitate.
Thanks in advance!

Cheers

 

[EarthDog]

At idle, the voltage stays around 1.32V, and the core speed is around 4.2GHz. However, when I run a CPU-intensive task (like an x265 encode), the voltage drops to about 1.05-1.10V, and the clock speed decreases to 3.8-3.9GHz.

Run Intel XTU and check the throttling reasons...

But if you're hitting 100C, it's throttling back due to temperatures.

What CPU cooler are you using??
Updated to the latest BIOS?

• Disabled/enabled XMP—no effect.
• Enabled/disabled OC mode in Voltage Configurations—no effect.
• Changed LLC (Load-Line Calibration) from Level 3 (default) to Level 2, then Level 1—this had no noticeable effect, which was surprising as I expected it to address the issue (See manual page 49).

The only thing that would change voltage is LLC, the others wouldn't have any affect.

 

[djesteban]

Hey EarthDog, thanks for the quick reply!

Run Intel XTU and check the throttling reasons...

But if you're hitting 100C, it's throttling back due to temperatures.

What CPU cooler are you using??
Updated to the latest BIOS?

Ran it yesterday and yes it did Thermal throttle when getting in the 95-100C, but what stood out was that I also had Power Limit Throttling warning to yes most of the test duration... I mean my PSU is a MSI MPG A1000G PCIE 5, 1000W, so it should be enough to handle the load right?? I read that Thermal Throttling and Power Limit Throttling warnings in Intel XTU are kind of related, is that true?
Like I get the fact that it's throttling back due to temperatures, but I'm surprised that it's slashing by like 0.3-0.4 V

My CPU cooler is the Noctua NH-D15 chromax.black and I'm on the latest BIOS revision (microcode 0x129)

The only thing that would change voltage is LLC, the others wouldn't have any affect.

Yeah I wish, but changing that value doesn't seem to have any effect on my system, default is Level 3, and I tried lowering it to Level 2 and then 1 and didn't see any changes regarding voltage drop...

 

[EarthDog]

Power Limit throttling has everything to do with the limits set on the board (nothing to do with PSU).

Raise the power limits in the BIOS. Maybe set Power Limit 1/2 to 253W (or 4096 = unlimited) and see what happens. At that point, you'll likely only be temperature throttling, but won't take nearly as hard a hit as you are currently.

Yeah I wish, but changing that value doesn't seem to have any effect on my system, default is Level 3, and I tried lowering it to Level 2 and then 1 and didn't see any changes regarding voltage drop...

Right. Just letting you know the other two options wouldn't do anything. Since you're power limit throttling, it makes sense that LLC doesn't adjust as it's banging off the limit already.

EDIT: In OC Tweaker, the CPU Config section, towards the bottom are the power limits (Short and Long Duration Power Limits)... what are they set at currently? Can you take a screenshot and drop that image in here?

But yeah, maybe reset to defaults, enable your XMP again, then raise those limits and see what happens.

 

[djesteban]

EarthDog
First, I just want to thank you for your help!

In OC Tweaker, the CPU Config section, towards the bottom are the power limits (Short and Long Duration Power Limits)... what are they set at currently? Can you take a screenshot and drop that image in here?

Couldn't find a way to take a screenshot, but the values were:

• Long Duration Power Limit : 125 (auto)
• Long Duration Maintained: 56 (auto)
• Short Duration Power Limit : 253 (auto)

Also, it seems that these auto values were set when I previously selected Air Cooler as the "cooler type".

The first test I performed is only changing the Long Duration Power Limit value to 253 and that definitively had an effect!! It kept my CPU to constant high voltages (around 1.32 V) and high core clocks, but obviously temps also idled in the red zone (95-100C).
I then slowly dropped that value and I'm currently testing Long Duration Power Limit at 185 and temps are hovering around 80C and core clock speeds averages 4.2GHz! I might drop that value a bit again, but this is pretty much exactly what I wanted!

Though I'd like to ask you if this is safe leaving it this way?

 

[EarthDog]

F12 takes screenshots in the BIOS (saves to usb stick).

So, yeah, ASRock has canned power limits set by the cooler type. You selected air and therefore the lowest power limits.

There's nothing wrong with letting it hit off the temp limit... you'll see it will lower it just barely. I think lowering it much past where it starts to throttle is wasting potential. These are meant to run that hot.

 

[djesteban]

All right I settled for 200 on the Long Duration Power Limit. I'm already getting a little over 15% better result on my x265 encode tests, it's amazing!
Thanks a bunch again for your help! Cheers!