Question Main Slot Won't Boot as PCIe 4.0.

Maikurosofuto

Commendable
Oct 24, 2019
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After trying to narrow down the cause (https://forums.tomshardware.com/threads/windows-10-stuck-on-loading-dots.3745394/#post-22615583)
I've found how to reproduce it, simply setting in bios the first slot as auto or PCIe 4.0 will make my Windows unable to boot 99% of the time. It posts and when I manage to get into windows with PCIe 4.0 everything works fine, so I don't have any clue of what's happening, already replaced the MOBO and the same issue occurs.
Setting it to PCIe 3.0 or using the bottom PCIe slot, which is PCIe 4.0 x8 connected to the chipset, boots flawlessly.

I'm on Windows 11 right now, but that's not really relevant, just making clear because of the video title, the problem is exactly the same with Windows 10.
View: https://www.youtube.com/watch?v=IUvfobmBrC8


For me, it's either the CPU or a BIOS issue, but since it works flawlessly when I manage to boot, I can't really see how it's the CPU. Hope someone with a better experience/knowledge can help me out on this, thanks in advance.

My specs in case you have signatures disabled:
Ryzen 9 5900X
GALAX GeForce RTX 3070 SG
ASUS TUF Gaming X570-Plus
32GB (2x16) Corsair Vengeance LPX 3600MHz
SK Hynix Gold P31 1TB + Crucial MX500 1TB
EVGA CLC 360
XPG Core Reactor 750W
 

popatim

Titan
Moderator
So the top Gen4 slot is having issues negotiating back down to Gen3 you think?

Are you on the latest Bios?
 

Maikurosofuto

Commendable
Oct 24, 2019
100
15
1,615
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So the top Gen4 slot is having issues negotiating back down to Gen3 you think?

Are you on the latest Bios?
The top slot only doesn't work properly at PCIe 4.0. I'm using the latest non-beta BIOS.
 

DRagor

Illustrious
Mentioned replacing mobo - to same model or it was different previously? It seems to be well known problem that some mobo/GPU combinations have problem when set to 4.0.
Btw, if it works when set to 3.0 why not leave it there? Performance difference should not be meaningful I think.
 

Maikurosofuto

Commendable
Oct 24, 2019
100
15
1,615
7
Mentioned replacing mobo - to same model or it was different previously? It seems to be well known problem that some mobo/GPU combinations have problem when set to 4.0.
Btw, if it works when set to 3.0 why not leave it there? Performance difference should not be meaningful I think.
Same model.
About the PCIe 3.0 and 4.0 performance difference, for now it's virtually zero, but I'm always upgrading my hardware whenever I can, so that PCIe version may make a notable difference in the near future.
 

DRagor

Illustrious
Same model.
About the PCIe 3.0 and 4.0 performance difference, for now it's virtually zero, but I'm always upgrading my hardware whenever I can, so that PCIe version may make a notable difference in the near future.
So different motherboard model might not have such problems. This model might not have such problems in the future thanks to BIOS updates. Finally when you upgrade your GPU the new one might not have such problem just because it is different model. If you have to solve it now I would suggest changing motherboard to different model.
 

Maikurosofuto

Commendable
Oct 24, 2019
100
15
1,615
7
So different motherboard model might not have such problems. This model might not have such problems in the future thanks to BIOS updates. Finally when you upgrade your GPU the new one might not have such problem just because it is different model. If you have to solve it now I would suggest changing motherboard to different model.
I'm starting to suspect it's a CPU defect, I'm contacting AMD's support to see if they can confirm that, I might try a RMA, and depending on how long the support takes to to confirm or deny it, I'll do it next week since my warranty expires next month.
Here's another video of how it behaves with PCIe 4.0.
View: https://www.youtube.com/watch?v=jHg4dr9hr4M
 

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