ASROCK H310D4-P1 User Manual page 50

H310D4-P1
CSM (Compatibility Support Module)
CSM
Enable to launch the Compatibility Support Module. Please do not disable unless
you're running a WHCK test. If you are using Windows 8.1 64-bit and all of your
devices support UEFI, you may also disable CSM for faster boot speed.
Launch PXE OpROM Policy
Select UEFI only to run those that support UEFI option ROM only. Select Legacy
only to run those that support legacy option ROM only. Select Do not launch to not
execute both legacy and UEFI option ROM.
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