[SOLVED] Weird behavior CPU Temp sensor - Gigabyte Aorus B450 PRO

[dragonelf37]

Since i have upgraded my gaming rig a few weeks back i noticed the fan curve was quite steep and noisy.
While checking the CPU temps, i noticed some weird behavior in the package temps.
It seems it is stuck in some kind of loop starting at a temp for instance 48 and -1 every second until 39 after it will switch to 48 again.

Hardware:
MOBO: Aorus B450 Pro
CPU: Ryzen 7 3800X (no OC)
Cooler: Noctua DH-15 (2 fans)

What i have done so far:

• I checked in HWMonitor and BIOS which both gave showed the same issue. It is only the CPU temp that is having this issue, while looking at voltages/load of the CPU and temps of other components all seems normal.
• I tried updating the BIOS.
• I reseated the CPU.

To me it seems a software since the temperatures are increasing and decreasing with the load, however i can't seem to find others with the same issue.
Anybody who has encountered this before or has some more info about this behavior on MOBO's?

 

[CountMike]

Use https://www.hwinfo.com/ as only 3rd party accurate with Ryzen and Ryzen Master from AMD.
Looking at BIOS is also not accurate as cooling and power saving features are not implemented until you save and close the BIOS.

 

[dragonelf37]

Use https://www.hwinfo.com/ as only 3rd party accurate with Ryzen and Ryzen Master from AMD.
Looking at BIOS is also not accurate as cooling and power saving features are not implemented until you save and close the BIOS.

I tried hwinfo and indeed the temperature loop is gone. However the motherboard still reacts to the looping temperature of the BIOS. Is this fixable?

 

[drea.drechsler]

I tried hwinfo and indeed the temperature loop is gone. However the motherboard still reacts to the looping temperature of the BIOS. Is this fixable?

In HWInfo, look at Tdie and Tctl (it may be shown as Tdie/Tctl) to see correct CPU internal temperature.

What do you mean by temperature loop? It is very much normal with Zen processors for temperature at idle and low loads to jump fairly high then ramp back down quickly. It's simply a result of the aggressive boost behaviour that raises voltage during boosts and the tiny 7nm chiplets. If fan curves aren't adjusted that will make them pulse up high and then back down too.

The best fan adjustment is to set a flat, barely audible fan speed (or one that's not bothersome) from 0 degree up to about 65-70C or so then start ramping up from there. That way at idle and low loads it will stay quiet but be able to respond to truly heavy loads when the processor really heats up.

 

[dragonelf37]

The best fan adjustment is to set a flat, barely audible fan speed (or one that's not bothersome) from 0 degree up to about 65-70C or so then start ramping up from there. That way at idle and low loads it will stay quiet but be able to respond to truly heavy loads when the processor really heats up.

This seems to have helped a lot. I had the curve set to low up to 50C with 75C at airplane mode.
I was not counting on the impact of the boost behavior.

 

[drea.drechsler]

This seems to have helped a lot. I had the curve set to low up to 50C with 75C at airplane mode.
I was not counting on the impact of the boost behavior.

Do keep in mind that Ryzen Tjmax is 95C; I reserve airplane mode for 90C or so. But it's also true the boosting algorithm starts pulling frequency about 75C which makes a 240mm AIO a nice cooling upgrade.