WHEA-Logger 18 (Cache Hierarchy Error) only in BF6 with RX 9070 XT + 5800X3D on B550. Replaced CPU (x2), PSU and RAM, still crashing. Card or motherboard? Any solution!!

[u/zipkilot]

Specs:

CPU: Ryzen 7 5800X3D (tested two different units)

Motherboard: Gigabyte B550 Aorus Elite V2 rev 1.5, BIOS [version]

GPU: [brand] RX 9070 XT, bought mid-August 2026

RAM: 32GB DDR4 (originally G.Skill Ripjaws 3600, now a different replacement kit), running at 3200, XMP off

PSU: [model, wattage] (already replaced once, previous: [model])

OS: Windows [10/11], AMD Adrenalin [version], installed clean with DDU

The problem

Hard reboot with no BSOD. Event Viewer shows WHEA-Logger Event 18, Error Source: Machine Check Exception, Error Type: Cache Hierarchy Error, Processor APIC ID different every time, followed by Kernel-Power 41.

Battlefield 6 reproduces it reliably within 10 minutes.

Apex Legends and CoD: they used to crash too, but have been stable for days since I set LLC to Medium (see below).

Other symptoms: one DEVICE_HUNG driver crash in Apex (fixed after DDU + driver reinstall), monitor occasionally goes black for a second at idle, and a USB controller once showed Code 43.

History: the same motherboard was fully stable with a Ryzen 5 5600X + RX 6700 XT. Problems started after upgrading to the 5800X3D + 9070 XT.

What I've tried

CPU: two different 5800X3D units, same crashes (the first one was sold and works fine for the buyer).

PSU: replaced, no change.

RAM: replaced the kit. MemTest86 passes, XMP off (3200 JEDEC).

BIOS: loaded defaults, PBO off, Core Performance Boost off, Global C-State Control off, PCIe forced to Gen3, SoC voltage 1.10V → 1.148V (no difference), CPU Vcore LLC + SoC LLC set to Medium (helped Apex/CoD, not BF6). Resizable BAR/SAM currently off.

Stress tests: OCCT CPU and OCCT Power (CPU+GPU) for ~25 min with zero errors. Only gaming triggers it.

GPU: reseated many times, clean driver install with DDU. [Separate PCIe power cables / no daisy-chain: yes/no]

[Registry: MPO disabled (OverlayTestMode=5) + TdrDelay=10 / TdrDdiDelay=20: done / not yet]

[FreeSync off: done / not yet]

[Adrenalin power limit -10%: result]

[FPS cap at 60 in BF6: result]

Planned next tests

Moving the GPU to the second (chipset) PCIe slot to rule out the primary slot / CPU lanes.

Clean Windows install on a separate drive.

My questions

Has anyone with a 9070 XT (or 9060 XT) on AM4/B550 seen WHEA 18 that only shows up in BF6?

Since CPU, PSU and RAM are ruled out, does this point more to the card or to the motherboard/PCIe?

Anyone with the B550 Aorus Elite V2 running a 9070 XT stable in BF6? Which BIOS version?

Any fixes I've missed before I send the card in for RMA? I can't easily test it in another PC, and I'd rather not ship it without being sure.

Thanks in advance!

[u/LongMustaches]

Did you install chipset drivers?

Did you try win10? Win11 is known to override drivers which can cause these issues. Either disabl;e those automatic updates (google it) or try win10.

[u/zipkilot → u/LongMustaches]

I install fresh windows 11. I update everything.

[u/LongMustaches → u/zipkilot]

I update everything.

Yes, and then windows decides to update as well and the drivers get fucked.

Since you haven't tried older driver versions, it might be possible that the drivers you're (or windows) are using have this bug.

[u/zipkilot → u/LongMustaches]

Yes. To install a windows 10 isn't big deal. But I have the same issue after 2 months. I tried everything

[u/lamp7777]

I had pretty much the same experience on R5 3600 and 5700 XT. Stress tests didn't show issues, some games worked perfectly (even graphics intensive ones), while others like BF2042 had random sudden reboots with the same error. Would have saved myself a lot of trouble if I just tested another GPU in my PC immediately instead of looking for issues with CPU/RAM, reinstalling Windows etc. RMA'd the card and the new one had no issues.

[u/zipkilot → u/lamp7777]

I can't rma again part from my pc. I did that one