Question Updated title. Is it safe, and stable to leave PC in CSM? not UEFI?

[Daynhg]

Hi.

Can anyone help please.

Tonight I swapped 3 old fans for 3 mnew ones. Then swapped my existing 250w 9080ti, that has never had a problem, for ever, for a new 200w 4070 in my other PC. (below)

‣ MSI MAG B560M MORTAR WIFI Gaming Motherboard, M-ATX
‣ Intel i5-11400F
‣ CORSAIR CMK 64G X4M2E3200C16 VENGEANCE LPX 64GB (2 x 32GB) DDR4 3200
‣ BE QUIET BK021 Dark Rock 4 135 mm Silent Wings Fan CPU Cooler - Black
‣ 1 x M.2 gen 3 nvmes.
‣2 SATA SSDS
‣3 x Noctua redux 120mm PWM case fans
‣ Evga Psu 650W Supernova 650 G5 Atx Mod 80+G

It all switched on, including GPU.

Then took me to bios, but after exiting, it takes me right back to bios.
So I swapped the GPU back to the old one, that I have never had a problem with.
But the exact same bios loop. It starts in bios, and when leaving bios, just black screeen for a few seconds and goes back into bios.
I see a flash of something for a split second sometimes at the bottom of the screen.

I have tried everything I can think of.
As well as Googling for hours.

‣ Turned completely off then on.
‣ Tried disabling secure boot.
‣ Tried reseting the bios to factory optimum default.

I cant see any reference to either GPU in the biops, but Im not sure if this is normal.
As all seems to be working , in the case, and the bios?

Quick note.
I took the 9080 ti out a few weeks ago to put in the NMMe, no issues, it went back in, and all was fine.
So have no clue what happened tonight.

Any help really appreciated.
Thank you.

 

[Lutfij]

Evga Psu 650W Supernova 650 G5 Atx Mod 80+G
How old is your PSU?

MSI MAG B560M MORTAR WIFI Gaming Motherboard, M-ATX

You have BIOS updates pending;
https://www.msi.com/Motherboard/MAG-B560M-MORTAR-WIFI/support

Did you remove all GPU drivers using DDU prior to removing what I'm assuming is your GTX980Ti? I say assume since Nvidia never made a 9080Ti unless you're from the future. Got a link to the RTX4070 you got as a replacement to your GTX980Ti?

 

[Daynhg]

Evga Psu 650W Supernova 650 G5 Atx Mod 80+G
How old is your PSU?

MSI MAG B560M MORTAR WIFI Gaming Motherboard, M-ATX

You have BIOS updates pending;
https://www.msi.com/Motherboard/MAG-B560M-MORTAR-WIFI/support

Did you remove all GPU drivers using DDU prior to removing what I'm assuming is your GTX980Ti? I say assume since Nvidia never made a 9080Ti unless you're from the future. Got a link to the RTX4070 you got as a replacement to your GTX980Ti?

After hours of reading, watching etc.
Its Working!

I read everywhere to keep the bios in UEFI.
But after pretty much altering everything I could safely think of. I just tried enableing CSM.
And it all works now.

I thank you for your help above.
And have just 1 last very quick question. I hope you dont mind they are very quick.

Im not sure how safe, or stable it is to run a PC in CSM?

1-- Is it safe, and stable to leave it like this?

Thank you again for any help on this.

 

[CountMike]

Hi Lutfij

After hours of reading, watching etc.
Its Working!

I read everywhere to keep the bios in UEFI.
But after pretty much altering everything I could safely think of. I just tried enableing CSM.
And it all works now.

I thank you for your help above.
And have just 1 last very quick question. I hope you dont mind they are very quick.

Im not sure how safe, or stable it is to run a PC in CSM?

1-- Is it safe, and stable to leave it like this?

Thank you again for any help on this.

Whole confusion is about about windows and if they were installed in CSM or UEFI mode. If installed in UEFI mode, system disk should be formatted as GPT, and if CSM, it can be MBR. Only Windows 11 require UEFI and GPT. "Safety" has nothing to do with it.

 

[Daynhg]

CountMike​

Thank you for the reply.
And the help.

 

[SkyNetRising]

Im not sure how safe, or stable it is to run a PC in CSM?
1-- Is it safe, and stable to leave it like this?

If windows was installed in legacy/CSM mode, then you can boot in legacy/CSM mode only.
If windows was installed in UEFI mode, then you can boot in UEFI mode only.

You can not randomly change this setting in BIOS and expect your pc to boot afterwards.
You're going to have to change partitioning style of your OS drive or reinstall windows.

 

[CountMike]

Actually, W10 and 11 installed in UEFI mode usually run in CSM mode too-

 

[SkyNetRising]

Actually, W10 and 11 installed in UEFI mode usually run in CSM mode too-

No.
Legacy/CSM mode requires MBR partitioning.
UEFI mode requires GPT partitioning.
A drive can not be partitioned in UEFI and MBR modes simultaneously. It's one or the other.

 

[CountMike]

No.
Legacy/CSM mode requires MBR partitioning.
UEFI mode requires GPT partitioning.
A drive can not be partitioned in UEFI and MBR modes simultaneously. It's one or the other.

My W11 does it just fine and so did W10 on multiple systems.

 

[SkyNetRising]

My W11 does it just fine and so did W10 on multiple systems.

That simply means - your called CSM mode is not legacy/CSM exclusive and actually supports booting in UEFI mode as well.
One mode is tried first and then after boot failure second mode is tried.

You can check your boot mode with msinfo32

 

[CountMike]

That simply means - your called CSM mode is not legacy/CSM exclusive and actually supports booting in UEFI mode as well.
One mode is tried first and then after boot failure second mode is tried.

You can check your boot mode with msinfo32

CSM and Legacy modes are not same thing, even the name shows it.

 

[SkyNetRising]

CSM and Legacy modes are not same thing, even the name shows it.

Obviously.
CSM mode is necessary for UEFI system to be able to boot in legacy mode.