What is CSM and do I need it enabled?

[chrisjordan7651]

So, if CSM is disabled for compatibility reasons, why does my Windows 10 boot without a hitch from a non-EFI m.2 drive? And what ASUS suggests for people who only have one UEFI installation of Windows 10. CSM can be turned on or off. In any scenario, UEFI is enabled. First... Because I'm just concerned with CSM, I'm not interested in Secure Boot. With so many activities, a SATA III SSD and motherboard startup time of 30-35 rear 38 seconds isn't bad. I can't answer for your board, but I had to keep the CSM activated on a similar build 7700K and M9F to allow it to boot from the USB. I don't recall experiencing any problems after turning off the feature. When Windows won't start due to an issue like this, I went back a step and let Windows boot, then rebooted to safe mode, then turned CSM off, saved, and exited. The computer will thereafter start in safe mode. restart...done

[Jimbo93]

So, if its there for compatibility reasons, how come my Windows 10 boots from a non EFI m.2 drive without any problem with CSM is disabled?

There must be a EFI boot partition somewhere you didnt know was there. Look in the bios at the boot options and youll see it.

[chrisjordan7651]

Ok, Let me check