Ryzen 9 Temperature Jumps

I recently build a new PC with a Ryzen 9 3900x.
I noticed variations in CPU Fan Speed and when looking at HWMonitor i noticed temperature jumps of around 10-15 degrees even under next to no load, which causes the Fan to ramp up. The temperature then reduces really quickly to the one it was sitting at before.

At first it seemed like the Windows 10 "Energy Save" (german Energiesparmodus) power mode helped, but it still does it, but more rarely.

My Setup:

• Gigabyte Aorus Ultra X570
• Ryzen 9 3900X
• AMD Wraith Prism Cooler
• Fractal Design R6 with a PWM Module (Cpu Fan is connected to it)

My question is: What causes these jumps and do i have to tolerate them or is there something i can do?