Question Temps on 3700x seem unreliable - even on the BIOS?

Dec 4, 2019
I just built a new PC and installed HWMonitor and was surprised to find that my CPU was idling at 50-60 degrees despite having a Corsair H100i set up with two exhaust fans. The other strange thing was that the temperature would flail around at random. It would go to 50 then immediately jump to 60 then countdown to 50. It would jump from 52 to 64 in a single moment, then bounce at random at temperatures in-between. In-game it typically lowers a little, and tweaking fan settings hasn't helped.

I decided this wasn't right, so downloaded Ryzen Master to see what AMD monitors reported, and on there I get a much more sensible 40 degrees at idle, with slow fluctuations of around 2-3 degrees.

So I knew my PC wasn't actually running hot, or at random, but that still leaves me with a problem. HWMonitor is getting the temp from the same source as the BIOS, meaning my fans spin based on the flailing temperature. This means that my fans are constantly going up and down in speed, which is quite annoying, and MSI Afterburner also gives me these flailing readings in-game which means I can't monitor my cooling performance when it matters most.

Of course, it could be that Ryzen Master is wrong and my CPU is just jumping up and down in temperature, but this seems a lot less likely to me.

Is there any way to change this? I've had a look around the BIOS, but I'm no expert and can't see a way to point the BIOS to the more accurate readings Ryzen Master gives me.

Mobo: MSI MPG x570 Gaming Plus
CPU: Ryzen 3700x
Cooler: Corsair h100i water cooler 240mm
GPU: ASUS GTX 1660ti
RAM: LPX Vengeance 2x8GB 3200mhz
PSU: Thermaltake London 550w Gold
Windows 10


Dec 4, 2019
Congrats on the new build.

You are not alone. The work around now is creating your own fan curves if possible through the bios to help reduce the fluctuations.

Hopefully this gets sorted out with a bios update.


Aug 17, 2019
Try to change the Power Options in Control Panel to Power Saver Mode... That reduces the power to the CPU from 1.4 v to 0.95 volts which will drop temps in the 30s. The CPU will still go into Turbo mode when needed. But this mode tends to be very conservative in ramping CPU speed up. You can change the Power Options to AMD High Performance when needed...

If you do not have the AMD power options listed, you need to install the AMD X570 chipset drivers and reboot. That could also be part of the problem...
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May 2, 2011
Just finish my build with my 3800x. Same problem as well, my idle temps on hwinfo is 40-50 and it constantly jumps in between. My stock fan curves were set to go to 100% at 50 c but I had to change it so that it doesn't keep ramping up and down. I'm using a kraken x72.
Hopefully this gets sorted out with a bios update.
It won't, that's why they have the ability to set up custom fan curves. They leave it to the OEM to set up fan curves since they know what hardware is going in the system... CPU, cooler, GPU, case, and case fans all contribute. And oh yeah.... you're the OEM since you built it!

The best curve seems to be a barely audible fan speed up to about 60-65 C on CPU, then start climbing to 100% no lower than 95 C or so. That would be for a Wraithe or other air coolers that scream at 100%... an AIO or big, slower fan coolers you could set the 100% point lower depending on what you prefer.