[G834JZR / Strix G18] Suspected memory controller (IMC) fault: dual-channel-only instability, single sticks test clean

Testing points to the CPU's memory controller (IMC), not a bad RAM stick or bad slot. Either 16GB stick tests clean in isolation in either slot, but any dual-channel pairing reliably reproduces a memory error under load. BIOS on this chassis exposes no memory frequency/voltage/timing controls, so I can't try a DDR5-4800 downclock or a small SA/IMC voltage bump myself. Posting in case this is a known pattern on this chassis. Not really expecting a fix, but would love if someone had one and could share it.

System

• Model: ROG Strix G18, G834JZR
• CPU: Intel Core i9-14900HX
• GPU: RTX 4080 Mobile/Max-Q
• RAM: 32GB (2× 16GB Samsung DDR5-5600 SODIMM, M425R2GA3PB0-CWMOD, stock/factory-matched pair, JEDEC 46-45-45-89, no XMP)
• BIOS: G834JZR.322 (latest available)
• OS: Windows 11 Home, build 26200

Symptom
Recurring crashes since ~June 2026: browser (Firefox + LibreWolf) content-process crashes, Python process crashes, and 2 full kernel bugchecks, all clustering together rather than looking like a single app's bug.

Kernel dumps

• 0x154 UNEXPECTED_STORE_EXCEPTION (memory-compression store path), 2026-06-06
• 0x50 PAGE_FAULT_IN_NONPAGED_AREA (classic bad-memory signature), 2026-06-23
• Both dumps have clean loaded-driver lists (stock Windows/ASUS/NVIDIA/Intel/Realtek only); ruled out malware/rootkit/driver conflict as cause.

Testing done

1. MemTest86 v11.7, 4 passes, stock 5586 MT/s: 0 errors. (Expected: doesn't stress all-core/thermal conditions well.)
2. TestMem5 0.13.1, Universal 2 @ LMhz, 32 threads, full 32GB dual-channel: 1 error in Test 8 at 1:32:58 (stock JEDEC speed, no OC).
3. Per-stick isolation (each stick alone, both slots tested, ~1.5h each): all pass, 0 errors. Neither module has a hard bad cell in isolation.
4. Slots swapped + both sticks reinstalled (dual-channel), TestMem5 DDR5 Intel @ anta777 (heavier config): error in Test 5 at 0:25:31, reproducing ~4x faster than the original run, and persisting after the slot swap (rules out a bad slot/contact).
5. Storage (CrystalDiskInfo, both NVMe drives): 0 media errors, healthy, ruled out.

• Is this a known issue on G834JZR/G834JYR?
• Any chance a future BIOS revision could either directly fix this, or expose basic memory tuning (even just a frequency step-down option) for cases like this?

Thanks!