UEFI question

I'v been building & upgrading computers for 23 years now I just built my latest P.C.

Anyway when I bought this motherboard (Asus P9X79 Pro) I thought that UEFI meant just some kind of different interface for the bios, after researching I see its a whole new ballgame.

I installed win7 64bit on my ssd with no problem but now that I found out about UEFI
I checked my win7 64bit and it is installed on MBR so I am using The old bios method.

problem is the whole time I had UEFI turned on in the bios.

Could this cause problems? or BSOD's?

I since have turned off UEFI.


Fantastic Member
Microsoft MVP
Something is not right here. You don't turn off UEFI. UEFI replaced BIOS. You can disable some features in UEFI - "Secure Boot" being a common one.


Excellent Member
Microsoft Community Contributor
Digerati is correct in that the UEFI bios is there and cannot actually be turned off. You can bypass it by installing the system in Legacy configuration, which is what you did.

Which configuration is used to install depends on how you boot the install Media. It should have options in the Boot Device Menu for either Legacy or UEFI versions of the boot media. You can turn off the ability of the system to see the UEFI options (or Legacy) during boot, but if you do not use the Boot Device Menu, the system will probably boot to the Legacy version by default.

If I may, could I ask exactly what settting you changed in the Bios? I have a P8Z77 board which is similar.

But the UEFI on/off question should not be a factor. If you are getting Blue Screens, you might check the BSOD forum for how to get help using the dump files.

Yes I stand corrected I did not actually turn it "off" I do understand that.
And as for setting's in BIOS I turned CSM=Auto & Secure Boot=Other OS

are these setting's correct for MBR?

I did check bsod forum, only thing they could tell me is that it was hardware related.


Excellent Member
Microsoft Community Contributor
I usually just leave the CSM set to Enabled and Boot Device Control to both UEFI and Legacy. The Secure Boot is Windows UEFI, but since you are using the Legacy install, they should not have any effect.

The only thing that might bite you is if you were to change the OpRom settings, which it doesn't look like you have.

Any BSODs are probably being caused by something else.

Ok thank you, and yeah I think I have pinned bsod to ram, got errors on it running memtest86
I have ordered new modules should be here by friday.

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