There are few things that we recommend setting up in your motherboard BIOS when mining. Most of these are not mandatory, but they could prevent unnecessary issues.
Every manufacturer has a different BIOS layout and different locations of settings, so you will have to find it yourself.
To enter BIOS, press DEL or F2 repeatedly at boot.
Boot priority
Set a boot priority (order) to the USB port that you want to boot from. Learn more here.
Primary video output
If possible, set it to PCIe (GPU output). Turn off internal GPU, this only eats up PCI lanes needed for external GPUs.
4G decoding
Enable 4G decoding if your BIOS/motherboard supports it. With this disabled, you will not be able to use more than 4 GPUs at the time.
Boot mode
Set boot mode to Legacy (non-UEFI). You can read a guide on how to disable the UEFI boot here.
Restore AC power loss
This is a cool feature in case your power goes off and comes back. Choose Last state or Power on in order for your rig to turn on automatically when the power comes back.