Ryzen 3000 Temp fluctuation

[kotolus]

My Smart Fan 5 Software by Gigabyte sometimes shows CPU temps fluctuating rapidly. The temps can go up and down again by about 10°C in less than 5 seconds. Can this possibly be a correct reading? I guess it's a problem with the temp sensors. I've read about multiple people having this issue, but couldn't find a fix. It's really annoying since my CPU is constantly between 50°C and 65°C in idle according to that reading, and the default fan curves get way steeper in the middle of those values, causing my fans to spin faster for a few seconds, which is pretty noisy. I don't really want to modify the curve a lot to push the fans to be silent through that entire span since I don't know if it's good for the CPU to constantly run that hot (we're still talking about mostly idle). 

 

I've got a good air cooler and a case with above average thermal performance according to Gamers Nexus. My MB is a Aorus X570 Ultra.

[HanZie82]

Telling us what CPU would be nice too.
But this is happening on my Ryzen 1700x as well. (On Gigabyte Auros X470 Ultra gaming (latest bios))
When idling it will just look like its counting to 10+ and then resets, really weird but it was trough different installs and OS's so im guessing its the CPU.

Like it idles 35C it will ramp up to 45C then reset back to 35C and do it all over. Constantly. Sometimes faster sometimes slower.
And sometimes it goes the other way around. hehehe. Im not to bothered but i can understand this being very irritating.

Really hope you find a solution, and i hope my input has shed a little light on this weird behavior.

[Jeppes]

Just adjust the fan curve. Easy solution.

[HanZie82]

Just now, Jeppes said:

Just adjust the fan curve. Easy solution.

Not a solution. Not even an answer to the question asked...

[Jeppes]

1 minute ago, HanZie82 said:

Not a solution. Not even an answer to the question asked...

It is. There is nothing wrong with his temp sensors.

[HanZie82]

1 minute ago, Jeppes said:

It is. There is nothing wrong with his temp sensors.

Ah ok like that. Sorry, but you souldve put that in there.
Now i look silly.

[Jeppes]

1 minute ago, HanZie82 said:

Ah ok like that. Sorry, but you souldve put that in there.
Now i look silly.

Its just that these 7nm Ryzens run warmer. Mine is 56C now with a game open in background. Yet it still hits only about 70C while under full load from Cinebench etc. I set my fan curve to ramp up over 1000rpm at 71C and steady 650-700rpm when below that.

[Midnitewolf]

From what I have seen and read, the temps fluctuating like that have to do with the boosting technology.  If  you monitor your cores, you will see that they are constantly boosting and receding over and over and over. The temp spikes come from the processor momentarily going from idle to boosting max.  However, generally the minute you put your CPU under any load, the temps seem to stabilize quite rapidly.

[kotolus]

Ty for the input. I've observed everything described here as well. I also set my fan curve roughly like Jeppes said. I don't think that's the perfect solution though since I think the CPU might be running unnecessarily hot during lower loads then. My CPU is also at around 50 - 65° without a game open, just some regular software for productivity (such as Microsoft Office, nothing really demanding), which is kinda weird. 

 

Another thing I've noticed when I wanted to test at which point the CPU will start throttling is that even when I turn the CPU fans off almost completely, the temp will not rise under the same low load. So either the readings are wrong or fan speed is nearly irrelevant until the CPU is actually under heavy load, in which case adjusting the fan curve so that it basically just has one spike is really the solution. The temp readings are still weird in any case as I can hardly believe that a single core boost will momentarily increase the CPU temp by 10°+.

 

The processor is a 3800X btw.