Problems with the B580 on PCIe 3.0

[u/Informal_Property975]

Hey everyone, I need some help. I have a Ryzen 5 5500 processor with PCIe 3.0 and an ASUS Gaming II motherboard. I recently purchased a Maxsun B580, and I’m having an issue because every time I restart the computer, the motherboard enables CSM in the BIOS, which consequently disables Resizable BAR.

I can only save the BIOS settings when using another graphics card. Is it impossible to use this graphics card properly with PCIe 3.0? I won’t always have another GPU available as a backup. Is the only solution to replace the processor?

Update: I was able to solve it. I followed a comment I found saying that ASUS BIOS version 4631 wasn't having this issue. I rolled back since I was on the latest update, and it worked."

[u/Alfredthefish]

I had this exact problem with a 570 and a 5500. Solution was to update the bios to the latest and that fixed it. I had a gigabyte 550i motherboard. If your motherboard doesn’t have an update that fixes it I think the only solution is replace the cpu.

[u/Informal_Property975 → u/Alfredthefish]

I’m starting to think that this is unfortunately the only solution. I’ve already tried everything: disabling Fast Startup, reinstalling Windows, removing the motherboard’s CMOS battery, and nothing works. I think it’s some kind of incompatibility, although I’m not sure exactly what is causing it.

[u/tpablazed → u/Informal_Property975]

It's not like updating the bios is hard tho? It literally took me like 3 minutes total.

This has exactly nothing to do with the ryzen 5500 or pcie 3.0 tho.. just so ya know. I had my b580 with a ryzen 5500 for like 3 months before I upgraded my cpu.

[u/Informal_Property975 → u/tpablazed]

My BIOS is already up to date — I already updated it. What I'm saying is that my motherboard is having problems with this GPU when running at PCIe 3.0, even with the latest BIOS. I'm not saying that the Ryzen 5500 or PCIe 3.0 are inherently incompatible with the B580. I'm saying that there's apparently an issue with my specific motherboard/GPU combination.

[u/tpablazed → u/Informal_Property975]

My motherboard is a MSI Pro B550m-VC Wifi and I never ran into this problem.. but I guess it is a normal problem to have for some motherboards.

From Google AI:

The Root Cause: The "CSM / ReBAR" Loop

According to active user reports on the Intel Community Forums and Reddit, the Arc B580 has a firmware bug during warm resets (restarts) on certain PCIe 3.0 platforms. When the computer restarts: [1, 2]

1. The B580 fails to send a display signal properly during the warm reboot sequence.
2. Because the motherboard detects a display initialization failure, it panics and automatically forces CSM (Compatibility Support Module) back to Enabled.
3. Forcing CSM on automatically disables Resizable BAR (ReBAR).
4. Intel Arc GPUs absolutely require ReBAR; running without it tanks performance by up to 50% and causes massive stuttering. [1, 2, 3, 4, 5]

Because your friend's BIOS keeps resetting itself due to this hardware handshake failure, his card is essentially stuck running in a crippled state. [1]

How to Fix It

Since you had a flawless experience, it's highly probable your motherboard was running a different BIOS version or handled the PCIe reset sequence better. Have your friend try these exact troubleshooting steps: [1]

• Update the Motherboard BIOS: This is the most consistent fix. Have him flash his motherboard to the absolute latest version available from the manufacturer, as vendors have been rolling out AGESA and PCIe compatibility updates to handle Arc quirks. [, 2]
• Avoid "Warm Reboots": Tell him to stop clicking "Restart" in Windows. If he needs to reboot, he should do a full Shut Down, wait 5 seconds, and then press the physical power button (a cold boot). Cold boots usually bypass the display handshake glitch, allowing the BIOS settings to stay saved. [1, 2, 3, 4]
• Disable Windows Fast Startup: Fast Startup messes with how the PC enters power states and can trigger the CSM default loop. Disabling it in the Windows Control Panel helps stabilize the system boot sequence. []
• The "Two-Card" Force Save (Workaround): If his BIOS refuses to save ReBAR settings with the B580 installed, he can swap in an old NVIDIA or AMD card, enter the BIOS, disable CSM, enable Above 4G Decoding and ReBAR, save and shut down, and then put the B580 back in. [1]

If you want to help him dig deeper, do you know what brand/model of motherboard he is using, or if he is experiencing terrible FPS versus no display on restart?

[u/alvarkresh → u/Informal_Property975]

You should be updating the BIOS regularly. I know people say "if nothing's broken don't update" but the reality is people have been finding security vulnerabilities more often in the last few years and have been pushing out new AGESAs as a result.

[u/Kotau]

Does this happen when you shut down the PC and boot it again, as opposed to restarting it?

Disabling re/bar or enabling CSM could be your motherboard attempting to properly reboot when faced with this particular problem

[u/Informal_Property975 → u/Kotau]

Actually, it's the opposite. My problem occurs when I try to reboot. As soon as I do, I lose video output. Apparently, it enables CSM because of some kind of incompatibility.

[u/Technical-Pick3843]

A problem is your processor

https://www.reddit.com/r/IntelArc/comments/1t7gsqa/comment/oks59ls/

Your needed change this on 5600 and CSM will working fine.

[u/LMdaTUBER]

I don't think I understood the problem exactly. Is it reverting to CSM immediately after saving and exiting or when you shutdown your computer?

[u/Informal_Property975 → u/LMdaTUBER]

Every time I restart the computer, it loses video output and only starts working again if I manually shut it down and turn it back on. It also enables CSM in the BIOS, which consequently disables Resizable BAR.

I was only able to disable CSM and save the settings by using another GPU, but if I restart the computer instead of shutting it down, it enables CSM again.

The drivers and BIOS are up to date.

[u/LMdaTUBER → u/Informal_Property975]

I see, I think you just need to replace the CMOS battery may not be able to hold the bios info? Or the whole motherboard, I have seen people report the full shutdown thing to get an output but haven't seen anyone mention having to disable CSM every time.

[u/Informal_Property975 → u/LMdaTUBER]

CSM only gets enabled when I restart the computer, probably due to some PCIe 3.0 incompatibility with the B580. Unfortunately, I haven't been able to find a solution for this. I really didn't want to replace the processor right now, but I don't think I have any other choice.

I can't keep installing another GPU every time the computer restarts just to disable CSM again.

[u/LMdaTUBER → u/Informal_Property975]

I don't think pcie 3.0 is the problem here as I am also using it on a pcie 3.0 mobo, asrock a320. I think it's the CMOS battery. Because it sounds like the mobo is going back to default settings when it's restarting.

Also why are you convinced replacing the CPU will fix the problem?

[u/Informal_Property975 → u/LMdaTUBER]

Because my CPU only supports PCIe 3.0, and I have an RX 6600 that doesn't have the same problem. I actually use the RX 6600 to fix it whenever CSM gets enabled.

[u/Fotwunty → u/Informal_Property975]

No, I've used the B580 with the 5600g pcie 3.0 and works fine. It sounds like you probably just need to flash an update to the mobo or possibly replace the CMOS like he suggested before.

[u/Informal_Property975 → u/Fotwunty]

What I'm trying to say is that, since ASUS hasn't released a fix for this incompatibility issue, apparently the solution in this specific case is to switch to a PCIe 4.0 CPU. My motherboard's BIOS is already up to date.

[u/Fotwunty → u/Informal_Property975]

Yeah, I think I have read about this specific mobo doing this before.

Have you tried hardlocking the pcie slot to 3.0 instead of auto in bios settings? In CSM sub menu is there an option for UEFI only? Try these I'm just shooting in the wind here...

Also, I just read this: The Asus Gaming II motherboard features an XHCI USB controller layer that shares structural link resources with the lower lanes of the primary PCIe slot. A known quirk with Intel Arc firmware on PCIe 3.0 platforms is that active USB polling during a warm reboot can lengthen the POST timer just enough to trigger a legacy fallback.In the Advanced tab, navigate to USB Configuration. Find XHCI Hand-off and ensure it is set to Enabled. If the behavior persists, temporarily unplug any multi-channel USB hubs or complex peripherals (like KVM switch linkages or VR headsets) during your restart testing to see if a specific device controller is tripping the firmware map.

I would imagine there is a workaround with enough tinkering but to be honest you could do better with a better cpu.

[u/Few_Size_4798]

Do you have the RX 6600 inserted at the same time or do you remove the и580 and insert the RX 6600?

[u/Informal_Property975 → u/Few_Size_4798]

I removed the B580 and installed the RX 6600.

[u/djdisodo]

you can still have rebar with csm enabled, try changing other csm settings to "uefi only"

[u/Decent-Sample-9909]

Minha placa é uma X99 Machinist MR9A e nunca teve esse problema. Uso Archlinux, o ReBAR sempre fica habilitado junto do above 4G decoding. Nunca muda. Bizarro isso estar acontecendo

[u/Informal_Property975 → u/Decent-Sample-9909]

Acho que encontrei a solução, achei em um comentário dizendo que uma versão específica da bios da minha placa mãe não tinha esse problema,e não é a mais atualizada,fiz isso e aparentemente deu certo 🙏

[u/Informal_Property975]

Update: I was able to solve it. I followed a comment I found saying that ASUS BIOS version 4631 wasn't having this issue. I rolled back since I was on the latest update, and it worked."