Undervolting AMD CPU (5800x)

[Pikatchu]

I just got myself a 5800x today, but the temperatures are all over the place.

 

On window startup, my CPU will hit 70C-80C when the background programs are starting up. 

On cinebench runs, it reach high 80s Celsius, did not see the magical 90+.

Voltages randomly shot up real high, 1.488V is the highest I've see for CPU VDD.

 

Is there a way for me to lower the over all voltage without significantly impact performance? Like the voltage curve control we have for GPUs.

 

EDIT: The CPU is cooled by a noctua nh-u12s, single push fan.

[IkeaGnome]

3 minutes ago, Pikatchu said:

I just got myself a 5800x today, but the temperatures are all over the place.

 

On window startup, my CPU will hit 70C-80C when the background programs are starting up. 

On cinebench runs, it reach high 80s Celsius, did not see the magical 90+.

 

Is there a way for me to lower the over all voltage without significantly impact performance? Like the voltage curve control we have for GPUs.

 

EDIT: The CPU is cooled by a noctua nh-u12s, single push fan.

Play around with PBO. AMD has these chips set to be super hot from the factory. You can undervolt with PBO quite a bit and not really notice any performance loss.

[Pikatchu]

1 minute ago, IkeaGnome said:

Play around with PBO. AMD has these chips set to be super hot from the factory. You can undervolt with PBO quite a bit and not really notice any performance loss.

I have tried it, but did not see any temperature improvement.

I can only get a stable negative 15 offset, 20+ will crash instantly when I run cinebench.

[IkeaGnome]

1 minute ago, Pikatchu said:

I have tried it, but did not see any temperature improvement.

I can only get a stable negative 15 offset, 20+ will crash instantly when I run cinebench.

I can't remember what I got mine down to. I want to say 25 or so. I wont be around my computer until the 1st of the month.

I didn't run into issues getting it to work. I'm also on a NH-L12S which is much smaller than the U12. Your motherboard isn't trying to over rule the settings is it? What are you using to monitor VDD?

[Pikatchu]

Just now, IkeaGnome said:

I can't remember what I got mine down to. I want to say 25 or so. I wont be around my computer until the 1st of the month.

I didn't run into issues getting it to work. I'm also on a NH-L12S which is much smaller than the U12. Your motherboard isn't trying to over rule the settings is it? What are you using to monitor VDD?

Monitoring VDD using hwmonitor.

This is where I am confused, should I use the bios to undervolt or Ryzen master software?

[IkeaGnome]

Just now, Pikatchu said:

Monitoring VDD using hwmonitor.

This is where I am confused, should I use the bios to undervolt or Ryzen master software?

BIOS. I did it through BIOS and had no issues. I figured trying to go through Master would be like trying to use a fan controller software to change fan curves. Might work, might not. 

[Pikatchu]

@IkeaGnomeSo I managed to get negative 23 to work as my highest, somehow. But for cinebench, I went from 14900s to 14300s. Temperatures are still in the 80s under cinebench. Score dropped but temp did not.

 

I have an 240mm AIO, thinking of slapping it on the 5800x and see if it helps with temp. But from my pass experience, it barely out performs the u12s.

[Pikatchu]

After some digging, I found that 5800x does run hot. People reporting 80C under stress tests, 40-50C idles, and 60+ while web browsing or doing something on the PC.

I have revert all setting back to normal right now, with XMP profile enabled and disabled PBO instead of leaving it on auto, going to let the CPU decide what it wants to do.

[antoipod]

Your temps seem about normal, the 5800x is a volcano of a chip and seems to be the hottest of the consumer ryzen chips.  Mine peaks at around 82C in cinebench on an hd-15 and this is after setting a mild undervolt  as shown in the video IkeaGnome linked with an offset of -18 all core.   If you want cooler temps, you could undervolt as instructed in the video and either set a negative auto overclock offset of -50mhz or reduce your PBO limits (ex: reduce EDC , PPT). You could also use ClockTuner 2.0 for ryzen to automatically set an undervolt.

[Npiet1]

So I've got the 5800x. You are completely right about it being normal for high temps.

I've managed to get it to 4.7ghz ((stock boost) at 53'c under stress test and 38'c at idle) using these settings for VRM (VRM temps are stable at 40'c underload). and forcing clock to 4.7ghz. Voltage was set to auto for the CPU. So no performance loss, while auto under-volting. I don't know if it will work for you but that's what I've done.

210418221500.BMP

[Pikatchu]

@antoipod

PBO did nothing for me for some reason, speaking of temps and voltage. I am running a u12s, motherboard is b550 tomahawk.

 

@Npiet1

Yeah, I set an voltage offset for all cores, -0.125. Which is kind of heavy. Judging from cinebench r23 scores, I lost about 5% multi core, and around the same for single core.

But with that setting, the CPU peaked at 80C, while normal use rarely exceeds 70C. Normal use includes gaming, web browsing, etc.

[Pikatchu]

Okay so, I have reset everything back to normal, removing the voltage offset.

 

I have change PPT to 105, TDC to 70, and EDC to 90. This granted me 73C max under cinebench load, but voltage still spikes to 1.465 briefly from time to time. However, it is better than stock, at stock it spikes to 1.498 or even to 1.512.