PCIe Gen 4 causes USB problems on B550/X570

graycorgi

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I posted this on Reddit where it's gotten around 200 upvotes and tons of comments with people having the same problem. I'm posting it here to make MSI aware of the issue as well, even though it affects all motherboard vendors. I already reported this to AMD and Nvidia.

With PCIe set to either Auto or Gen 4, and when using a PCIe 4 GPU such as a 3080, many people are having problems with USB devices - mostly on USB 2.0 ports but sometimes on 3.0 ports as well. I'm seeing tons of reports of this problem (some of which go back a whole year!). It doesn't seem limited to one specific vendor either.

For me personally, I have a 3080 FE, 5900X, and MSI Tomahawk X570. I am experiencing audio dropouts when streaming a game on Discord. The audio drops for both people viewing and also for me, the one playing the game. That problem almost entirely goes away if I move the USB dongle for my headset from a USB 2.0 port to a USB 3.0 port. I also get occasional tracking loss on my Valve Index in VR when trying to view desktop windows from within VR. All of my VR devices are connected to USB 3.0 ports on an add-in card. This is a brand new windows installation with all updated drivers.

Setting PCIe to Gen 3 in the BIOS fixes the problem entirely. Disabling Global C states has no effect, only limiting PCIe to Gen 3 fixes the issue. Raising/lowering voltages for things like SOC doesn't make a difference either. I see a lot of discussion about the Global C State issue including vendor comments from Gigabyte and MSI, but so far no vendor has commented on the PCIe Gen 4 issue. Hopefully this issue starts getting some more attention as more people get PCIe Gen 4 GPUs. Limiting myself to Gen 3 isn't the end of the world, but people shouldn't have to lose that 2% of performance just to have a properly functioning system.

Here are some of the many reports I have seen of the issue. There are a lot more, this is just a small sample:
Code:
https://community.amd.com/t5/processors/audio-crackling-and-usb-issues-with-pcie-gen-4-0/m-p/421978#M33917
https://www.reddit.com/r/AMDHelp/comments/e598ho/pcie_gen_4_and_rx_5700_xt_issues_affecting_usb_20/
https://www.reddit.com/r/MSI_Gaming/comments/k026eo/b550_edge_gaming_wifi_insane_usb_stutter/ge8q5bo/
 

mafst155002df

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Noticed this as well, my Teamspeak USB audio was crackling up during my Cyberpunk installation, both on my USB 2.0 ports as well as 3.0 ports (B550 Gaming Carbon).
Switched to PCIE 3.0 and the crackle has _mostly_ disappeared, I wouldn't say "completely" so I don't think this is an actual fix but more of a workaround.
Strangely I can't cause the crackle to appear using something like furmark / prime95 or high network load (, Cyberpunk preload causes it 100% reproducible though).
Wonder what it is exactly.

The USB lagging (stuck keys on a keyboard for example) will happen with FCLK 1700+ on my machine so I would consider the "crackling" and "stuck" USB ports 2 different issues.
Got the board stable and "nearly" working perfectly now using 1600FCLK + PCIE 3.0, but I don't enjoy missing out on features.
I'm very picky about my machine though, I don't accept "lag" and "stutter" and prefer a "smooth" experience over a "fast" experience.
 

Alan J T

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I have full Gen four CPU, GPU and Motherboard and have none of the problems reported perhaps it is a Nvidia issue
 

graycorgi

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I have full Gen four CPU, GPU and Motherboard and have none of the problems reported perhaps it is a Nvidia issue
You ever connect your audio device to the front USB 2.0 port and try to stream your game at 1080p on Discord? For me, the symptoms require very specific steps to reproduce. You (and probably most people) may never encounter or notice the issue.
 

Alan J T

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You ever connect your audio device to the front USB 2.0 port and try to stream your game at 1080p on Discord? For me, the symptoms require very specific steps to reproduce. You (and probably most people) may never encounter or notice the issue.
I only ever use USB audio I have the Onboard disabled And My curent headphones nor My RIG 800 have any problem with Audio no matter the USB port connected to. But I have noticed almost every one who has the Problem have a Nvidia GPU.
 

graycorgi

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Nvidia also has the dominant market share of GPUs. There were reports of this problem with the 5700XT from a year ago; I linked it in my original post. The steps to reproduce the problem are very specific (at least for me) so even if you had the problem you may not ever notice. I never have a problem with audio unless I stream on Discord (at least, that's the single place I've found so far). And that's only if I use my USB headset, only if I use the front USB 2.0 port, and only if I stream at 1080p60 or above quality. Setting PCI Express to Gen 3 fixes that, and it also fixes the very intermittent SteamVR tracking issues I get when I try to view my desktop from within VR. Not saying it couldn't be an Nvidia driver issue, I just think it's unlikely considering the devices affected are not related to the GPU at all and that the workaround is changing the PCI Generation on the motherboard which should be driver agnostic.

Other people have the problem way worse than me, to the point where their devices fully disconnect. Fortunately I am not affected that severely.
 

mafst155002df

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Just to add as I've been testing this further, my "crackling" is unrelated to USB.
I can hear it through my hdmi audio also and is solely related to Teamspeak somehow.
Meaning the only USB issue I had was related to a high FCLK (no problem with FCLK 1600).
PCIE 3.0 was still crackling, so I switched it back to PCIE 4.0 as it didn't matter.
 

jmkraapp155302d9

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I also have issue with USB in my X570 Unify motherboard (BIOS A82) with 5900X CPU, RTX3080 GPU and PCIE4 SSD.

My USB audio interface loses USB connection and causes audio dropouts. This happens when some heavy games (like Flight Simulator) are played and CPU/GPU are utilized fully. Disabling C-state does not help.
 
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mafst155002df

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I also have issue with USB in my X570 Unify motherboard (BIOS A82) with 5900X CPU, RTX3080 GPU and PCIE4 SSD.

My USB audio interface loses USB connection and causes audio dropouts. This happens when some heavy games (like Flight Simulator) are played and CPU/GPU are utilized fully. Disabling C-state does not help.
Please also post your FCLK if you know what it is.
 

graycorgi

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I have the USB issue at FCLK 1800, 1600, and 1066. It doesn't seem to matter what my FCLK is or what my DDR is running at.
 
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This issue affects my onboard audio and any usb audio device plugged into USB 2.0
Here is my saga and some specs.

After the last BIOS update I got tired of re inputting all the tuning values so everything is AUTO except for XMP, Fans and secure boot (disabled).
The audio breaks up mostly when getting steam notification messages while watching videos/gaming.
For the most part I thought it was the steam client on linux but after hearing it happen during some extended windows sessions (dual boot) with games that wont play on proton I found the threads above.

Currently I have 2 workarounds:
1. GPU audio seems unaffected but whenever the monitor goes to sleep so does my audio GG music.
2. I have a cheap ~$8 Sabre usb audio dongle plugged into one of the usb 3.1 slots with no issue.

GPU Note:
I am currently running an Nvidia EGVA Founder 1080GTX but before this was using a Gigabyte 5700XT (GV-R57XTGAMING-OC-8GD-rev-10)
The card was so unstable it would commonly crash the GPU driver in windows randomly while watching videos or gaming as well as crash my X11 Session in Linux.
Tried various things to and waited months with no fixes from AMD and no RMA from GB so its in now in a landfill somewhere.
(suspiciously enough the REV2.0 of the board is bigger and consumes 20 more watts? (GB CS told me this))

AMD RYZEN 7 3800X 8-Core 3.9 GHz (4.5 GHz Max Boost) Socket AM4 105W 100-100000025BOX Desktop Processor
MSI MPG X570 GAMING EDGE WIFI Gaming Motherboard AMD AM4 SATA 6Gb/s M.2 USB 3.2 Gen 2 HDMI ATX
CORSAIR Vengeance LPX 32GB (2 x 16GB) 288-Pin DDR4 SDRAM DDR4 3200 (PC4 25600) Intel XMP 2.0 Desktop Memory Model CMK32GX4M2B3200C16
XMP PROFILE 1 3200Mhz

.o+` ----------------
`ooo/ OS: Arch Linux x86_64
`+oooo: Host: MS-7C37 1.0
`+oooooo: Kernel: 5.9.14-arch1-1
-+oooooo+: Uptime: 1 hour, 9 mins
`/:-:++oooo+: Packages: 1001 (pacman)
`/++++/+++++++: Shell: bash 5.1.0
`/++++++++++++++: Resolution: 1920x1080, 2560x1440
`/+++ooooooooooooo/` DE: Xfce 4.14
./ooosssso++osssssso+` WM: Xfwm4
.oossssso-````/ossssss+` WM Theme: Default
-osssssso. :ssssssso. Theme: Adwaita-dark [GTK2], Adwaita [GTK3]
:osssssss/ osssso+++. Icons: Adwaita [GTK2/3]
/ossssssss/ +ssssooo/- Terminal: xfce4-terminal
`/ossssso+/:- -:/+osssso+- Terminal Font: Monospace 12
`+sso+:-` `.-/+oso: CPU: AMD Ryzen 7 3800X (16) @ 3.900GHz
`++:. `-/+/ GPU: NVIDIA GeForce GTX 1080
.` `/ Memory: 2605MiB / 32094MiB
 

Ragnador

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@jonathan.hane157002e1
The USB stutter/"crackling sound" issue with FLCK higher then 1600 is related to the Problem with the c-states mentioned in the Beta update section.
bypass is to disable c-states.
My Audio was crackling because my soundblaster g6 was overheating in high gain mode due to the stuttering, now i have a little molten rubber feet. But it still works.


The PCI-gen 4 issue mentioned here is something else


And there is an usb-hub issue with not updated windows 10, build should be higher then 19042.622 (check "PC-Info" current is 19042.685)
 

Mattech

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This is still an issue on latest MSI X570 Tomahawk BIOS with AGESA 1.1.9.0
Already said it over on Reddit, but thanks for confirming. Because of your previous post on Reddit, the very first thing I did when I turned this new system on a week and a half ago was switch PCIe 4.0 to 3.0. I haven't had a single issue since. And this computer has been rock solid. Now I just need to snag a 3080 lol.
 

vashinh153b02d8

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I've upgrade my computer last month. So, new Ryzen 5600X, with a MSI B550 main board and a NZXT H400i ATX Case, with Smart Device V1. I had the Case working before with another setup, no issues at all. After having all new hardware mounted and windows working.

1st issue i've noticed, a few seconds after initializing the Smart Device, CAM would lose the connection to the Smart Device. Pressing the "try again" button, the device was initialized again, just to lose the connection again after a few seconds. I only had 1 Fan plugged and the Led strip, CAM software was not exactly a concern.

image.png.59037b896aa0593880887b2450a915e3.png


Then came the hanging. Windows would freeze. Mouse was still visible and working, a few visual objects were clickable, but couldn't start Task manager or anything at all. Hard reset or forced shutdown was needed. My thoughts, were that the Smart Device was causing it. Noticed something very off with HWInfo

power_issue.png.b5d55338d97fcdf538db5424e4348309.png


This showed up and the values were skyrocketing, so I disconnected it and made some monitoring. So I've started searching for the issue and found this link, stating that there were some issues with USB Headers on newer motherboards, probably because of USB3.2 specs.

Just like i mentioned above, they were slow to reply, and i kept doing troubleshooting on my own. So I've managed to plug the Smart Device on a different USB port, not another USB Header, but a back IO Port. And it worked. No more connections lost to the USB Smart Device.

Still not sure why the devices don't get to work connected to the USB Headers.

Today I came across this post:
https://www.reddit.com/r/Amd/comments/lnmet0
The USB Connectivity issues were solved (temporarily) by setting PCIe to 3.0.
 

graycorgi

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This is still a problem on the latest AGESA 1.2.0.1 BIOS for the X570 Tomahawk (and I assume the other boards as well)
 

vashinh153b02d8

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This is still a problem on the latest AGESA 1.2.0.1 BIOS for the X570 Tomahawk (and I assume the other boards as well)
I Have a B550 Mortar WIFI. I've updated my BIOS, to AGESA 1.2.0.1 and it solved my USB issues. My computer now seems to be very stable. I don't even have to set PCIe to 3.0.
There's an issue with Bluetooth, but it seems to be related to the adapter or drivers for it, as it works fine with a USB Adapter.
 

dch4154502d9

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The USB 2.0 ports on my MSI B550-A Pro m/b don't work at all. They have power but that's it. Setting PciE to Gen 3 makes no difference.
 
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