Weird pc startup after upgrading MOBO and CPU

[KuLfi]

I have recently changed my CPU for Ryzen 5 5600X and mobo for Asus TUF GAMING B550-PLUS (WI-FI) and since then I'm experiencing problems when I turn on the pc. After pressing power button it takes ~6 sec. for everything to turn on (used to be instant) and when it finally starts all the fans run at max speed for a few seconds. Additionally I don't know why mobos rgb is turned on when pc is off. What may cause these issues and how can I fix them? TIA for your help.

 

P.S. I had to enable CSM in BIOS because there was 'No bootable devices found' error.

[Analog]

54 minutes ago, KuLfi said:

I have recently changed my CPU for Ryzen 5 5600X and mobo for Asus TUF GAMING B550-PLUS (WI-FI) and since then I'm experiencing problems when I turn on the pc. After pressing power button it takes ~6 sec. for everything to turn on (used to be instant) and when it finally starts all the fans run at max speed for a few seconds. Additionally I don't know why mobos rgb is turned on when pc is off. What may cause these issues and how can I fix them? TIA for your help.

 

P.S. I had to enable CSM in BIOS because there was 'No bootable devices found' error.

 

It is a good idea to post you full specs, not just the motherboard and processor that you have. Generally enabling CSM will make the system load slower. Considering that you enabled it, this might be what is causing your slow start ups. Consider reinstalling Windows using the GPT instead of MBR. Regarding the RGB, there should be a setting in the BIOS to turn it off while the computer is off. It should be something Aura-related. Alternatively you can download and install the Asus Aura software for Windows. It also gives you the option to turn off the LEDs when the device is powered off.