Ryzen 5 2600X: CPU temps swing all over. Normal?

I have a new build that has a 2600X in a ITX small form factor, so I have been monitoring the temps to make sure cooling is adequate. I haven't really paid attention to CPU temps in the past on my other computers.

The CPU temp swings all over the place very quickly, and I was just wondering if this is normal for how the newer CPU's are? Is the temp sensor in a more responsive location? At idle, it will sit at around 42*C. But as soon as you open a program or install something, it instantly jumps to like 57*C, then falls back down just as quickly to 47*C. and just goes up and down. Way faster than the heatsink could change temperature. The heatsink can't change 10*C in a second. The "motherboard" sensor reports changes much much slower. It will sit at 42*C as well and slowly raise to like 47*C under extended load.

It seems like it's not a big deal since the temps never get higher then 60*C, but it's the erratic behaviour that is new to me. Also I have the AIO fan to have it's speed based off the CPU temp so it's just constantly spinning up and down when I am actually running programs.

AS Rock B450 Fatality ITX
Thermal Take AIO 120mm water cooler

sounds normal to me. its reading internal temps so it will swing wildly. you need a custom profile for your fans. where they dont spin up until the higher temps are reached. so set them at like 25% until they reach 57c then ramp up to 100% at like 70c.

that sounds normal to me also. but i would hate that aio fan revving up and down. that's very noticeable like you hear in laptops. i'd prefer a constant hum.

fan speeds and triggers can be adjusted so that you can smooth out some of these temp swings and minimize how drastic of a step the fans have to make once a step is reached. ...so that it's more of a gradual change in fan sound vs abrupt changes.

Your fan and/or pump RPM curves just needs adjusting. Idling at 42c with an AIO tells me you have the RPMs way too low at lower temps, and you possible have too much of a jump in RPM once you get over 50c or something. . It should be set at a audibly tolerable level that can still dissipate sudden heat spikes.

I have most of mine set at around 40% under 40c, 55% for 40-60c, 70% for 60-75c, 80% for 75-80c, then 100% for anything higher, which I don't think I've ever seen on my 2700 mildly OC'd to 3.9MHz. My CPU rarely hits the 60's unless I'm encoding a video, and only hits 70's when running stress tests. Fans DO ramp up, but not from basic tasks, and only from the GPU when gaming. Your Fan speed and tolerable noise levels will vary. Play around with it.

Also, keep in mind that a fan's static pressure rating is a bigger deal at lower RPMs. Any fan can push air through a radiator when it's spinning at a couple thousand RPM, but can it keep that airflow/pressure at 600-700? Low RPM is why static pressure rating is important, for a quiet build at least.

overall though, nothing is going to stop your cpu temps from jumping instantly from 33c to 70c under full load with a modern cpu. Especially with ryzen3 cpu's at 7nm. The heat cannot be moved away from the cores fast enough to mitigate it using copper at ambient temps. But pretty much any current or previous gen cpu will be in the boat of instant temp reporting. It's what allows them to auto-overclock (boost) safely.