Bootable devices such as onboard I/O or PCIe express cards require option ROM and I/O space to boot. However the total option ROM and I/O space for the system is limited by the PC architecture and is allocated automatically when the system is booted. If your system includes many potentially bootable devices, you must decide which ones you wish to boot from, and configure the BIOS to allocate these resources to them.
Option ROM is also required to run some configuration utilities, such as RAID configuration utilities.
This section includes: