[SOLVED] Why are the CPU and GPU fans spin during sleep mode?

[Giant Hunger]

I've recently build a PC and install windows 11, the spec is a xeon x5550, 16 gb ECC, hd7770, x58 Chinese OEM Mobo

After i install windows and used it for a while, i put it on sleep mode yet the CPU and GPU fans still spinning, the monitor, mouse and keyboard are off but the fans are still spinning. This is my first time building a server pc so i really don't know much. Is this a normal problem for server CPUs? What should I do to turn off fan during sleep mode?

 

[hotaru.hino]

The system may be entering S1 sleep mode instead of S3. You should be able to find and configure in BIOS which mode it enters in.