Question PC won’t boot to windows 10 after CPU upgrade ?

DAG93

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Feb 23, 2020
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Hello all,

I just upgraded from a Ryzen 5 3600 to a Ryzen 7 5800x3d. I want to be excited about it but my pc is stuck only booting to the bios. I selected the newest bios for my MSI x570 gaming edge Wi-Fi motherboard and installed it just fine. Booted the pc with my old cpu attached before hand to verify. Now the pc sees the 5800x3d but won’t boot to windows from my M.2. My second m.2 is not visible at all in the bios and just to confirm the pc was not trying to pick one over the other I took the secondary m.2 out and still nothing. I’m at a loss
 

DAG93

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Feb 23, 2020
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Okay so I was doing some digging before I posted this thread and saw a post which I will link below that mentioned something about Legacy boot which I could not figure out how to enable. I selected CSM instead of UEFI and it booted into windows… I can only assume I enabled legacy mode… but what the heck did I do and what does CSM do compared to the way it was before? Should I expect errors or performance loss?

 
Okay so I was doing some digging before I posted this thread and saw a post which I will link below that mentioned something about Legacy boot which I could not figure out how to enable. I selected CSM instead of UEFI and it booted into windows… I can only assume I enabled legacy mode… but what the heck did I do and what does CSM do compared to the way it was before? Should I expect errors or performance loss?

CSM = Compatibility Support Module . provides support for Legacy non-UEFI mode for BIOS. as it was before UEFI was invented. If Widows were installed in CSM/Legacy it will not BOOT if BIOS is in UEFI mode. If installed in UEFI mode it will BOOT in either mode.
 

DAG93

Commendable
Feb 23, 2020
79
3
1,545
1
CSM = Compatibility Support Module . provides support for Legacy non-UEFI mode for BIOS. as it was before UEFI was invented. If Widows were installed in CSM/Legacy it will not BOOT if BIOS is in UEFI mode. If installed in UEFI mode it will BOOT in either mode.
Thank you for the info! I’m very happy this was the fix! Would swapping out the processor have something to do with this? My install is less then 3 years old and although windows 11 has come out in that time I can hardly imagine it is legacy. Also at some point I will be switching to a 4000 series or 7000 series card. That being said will CSM keep me from enabling Resizeable bar?
 
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Would swapping out the processor have something to do with this?
My install is less then 3 years old and although windows 11 has come out in that time I can hardly imagine it is legacy.
Can you show screenshot from DIsk Management?
(upload to imgur.com and post link)

If windows is installed in legacy mode, it is possible to convert it to UEFI by using mbr2gpt utility.
 
Thank you for the info! I’m very happy this was the fix! Would swapping out the processor have something to do with this? My install is less then 3 years old and although windows 11 has come out in that time I can hardly imagine it is legacy. Also at some point I will be switching to a 4000 series or 7000 series card. That being said will CSM keep me from enabling Resizeable bar?
When you swapped CPU CMOS/BIOS was reset to factory defaults and in this case default is UEFI mode which is required by Windows 11 so TPM could work.
 

DAG93

Commendable
Feb 23, 2020
79
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Hello all! Sorry for the slow response, life gets the better of my drone time to time. I wanted to come and update this after I got a new GPU and could confirm the guide I found from an LTT video worked. The built in window’s utilitys worked so convert my system CSM to UEFI and I can confirm that resizeable bar works! Here is a link, I’d recommend pulling it up on a phone or separate pc.

https://www.maketecheasier.com/convert-legacy-bios-uefi-windows10/?amp
 

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