Fan does not start directly on boot up.

[Zeen7777]

Hello! I changed to Air Cooler recently because i have some issue with the AIO for now, will change it back sometime but now since im on Air cooling, when i boot up the PC the CPU fan does not start directly but like few seconds later, enough to give CPU Fan Error for the BIOS and i have to enter BIOS then exit BIOS so the system boots up because the fan gets to work normal after.

The cooler is combined a little bit, i use the heatsink from Be Quite Pure Rock with Noctua NF-F12 industrialPPC-3000 PWM for providing airflow to the heatsink and Noctua NF-F12 industrialPPC-2000 PWM from the back side of the heatsink to suck the air out to the back case fan.

The issue comes with the 3000 RPM Noctua fan, it's the fan that doesnt start directly after boot up. Wanted to mention additionally that the PSU is disabled while the PC is not working overnight dont know if this is the reason because of the PSU discharge, since this normally happens sometimes and its always at the first boot up after its been off electricity fully overnight, if i turn it off and turn it on a bit after its working fine.

The fan in general doesnt show performance issues during usage, its able to reach its max speeds and doesnt stop randomly or whatever, only the boot up thing happens.

With the AIO i didnt have issues related to that.

The PSU isnt very good brand, its standard Plus 80 750W PSU, 3 years old for now, as the whole system also.

Specs:
Motherboard: Asus Prime B550 M-K
CPU - AMD Ryzen 9 5900X
GPU - Palit GeForce RTX 3070 GamingPro OC v1
RAM - 16 GB 3200 mhz
PSU - 750W Plus 80

 

[kiddagoat]

I would try a different fan header to start. The CPU Fan error will occur still but you can see if the fan starts up right away on a different header.

If so, it could be the fan profile in the BIOS. With the AIO the pump will typically run off the CPU Fan header and doesn’t require much of a PWM signal to start.

I have noticed over the years that different fans do have different start up signals in relation to the PWM. My Vadars will stop spinning at about 12% PWN. My Cooler Master Sickleflow start and stop at about 20% PWM.