Recently, I noticed my computer is making a frequent meow noise when it is shut down or in sleep mode. It cries like every 0.8 seconds.
I figured out that the noise is caused by the slightest movement of the case fan. The fan should not spin at all when the PC is off, but it seems the fan is flickering a bit and making weird noises all day.
I also noticed this phenomenon would stop when I configured the RPM of the fan to be fixed at 0 RPM using NZXT CAM. But this is not ideal.
Considering all this information, I assume this is a bug in NZXT CAM or the Smart Device V2.
Version of NZXT CAM: 4.57.2
Version of Smart Device V2 firmware: 1.12
Update:
I figured out this would only happen when a certain device (Huion Kanvas Pro 16) is connected to a port on PCIe USB expansion card. The Huion display was making a frequent click sound which was in sync with the fan's noise. When I plugged the Huion into another port the noise problem was solved. Probably it is due to a USB port being broken or Huion being broken.