Ryzen 5 5600 - "Data Fabric Sync Flood" / MCE crashes (Stable on Windows)

Issues & Assistance
1

Hi everyone,

I’m experiencing random reboots/crashes on CachyOS with my Ryzen 5 5600. The system is rock solid on Windows 11 (dual boot), but on Linux, I keep getting fatal hardware errors shortly after booting or during light usage.

Here is the error from dmesg:

[ 0.873576] x86/amd: Previous system reset reason [0x08000800]: an uncorrected error caused a data fabric sync flood event
[ 0.873600] mce: [Hardware Error]: Machine check events logged
[ 0.873601] [Hardware Error]: System Fatal error.
[ 0.873606] [Hardware Error]: CPU:1 (19:21:2) MC5_STATUS[-|UE|MiscV|AddrV|PCC|TCC|SyndV|-|-|-]: 0xbea0000001000108

My Hardware:

  • CPU: AMD Ryzen 5 5600

  • Motherboard: Asus PRIME B450M-GAMING/BR

  • GPU: AMD Radeon RX 7600

  • Kernel: CachyOS (bore-lto)

What I have already tried (Issues persist):

  • Curve Optimizer: Disabled (Set to 0).

  • Global C-State Control: Disabled in BIOS (and tried processor.max_cstate=1 in GRUB).

  • Power Supply Idle Control: Set to “Typical Current Idle”.

  • LLC (Load Line Calibration): Set to High.

  • RAM: Using standard DOCP profile (Tested and stable on Windows).

Since this “Data Fabric Sync Flood” only happens on Linux, I suspect it’s related to how the kernel handles power management or voltages for the Infinity Fabric on this specific motherboard, but I ran out of ideas.

Does anyone know a specific fix for this B450/Zen3 combination?

Thanks!

2

Have you tried a different kernel?

3

Yes, I tried the default kernel (linux-cachyos) before and the same thing happened. I can also try the LTS kernel to see if it helps.

4

Interesting, because I have exactly the same processor and chipset. Only my motherboard is Asrock. But I don’t have such problems. I even overclocked the processor by +200MHz and it works up to 4600MHz.

My Kernel: Linux 6.18.2-1-cachyos-bore

5

I decided to test the LTS Kernel to see if the issue persists. I played some Overwatch (which was the easiest way to trigger the crash on the BORE kernel) and, so far, it hasn’t crashed.

However, I noticed a difference in behavior: on the LTS kernel, the CPU boost tops out at 4.6GHz, whereas on Windows and on the BORE kernel it hits 4.65GHz. It seems stable so far, but I haven’t tested it extensively yet, so I can’t say for sure if the problem is completely gone or if I just got lucky.

It’s also worth noting that with the BORE kernel, the system crashed even when I was simply watching YouTube (low load), so the instability wasn’t exclusive to high loads.