Question: The SB fan on my X570 motherboard is not spinning. Is this normal?(1/1/2021) Answer: Your motherboard might be using a semi-passive mode for this fan.
In this mode the fan will not spin at lower temperatures, and only become active at higher temperatures. This is normal. If you want to let the fan spin, you can select a different mode for the fan in BIOS.
Path: BIOS\H/W Monitor\SB_FAN1 Setting