X870E Nova D4 on restart/cold boot

Took the day to go properly over the situation.

Single dimm - 4d can occur (rarer then 2 slots)

GPU out - no change.

Took all nvme drives excpet windows system, same story.

Did alot and alot of manual running.

Patched 4.1 bios. Did alot ofanual adjustments to Processor droce strengths and impedances - and this greatly reduced 4d occurence.

By the end of the day, I spotted 4.2 update. Patched, so far tests go fine... We'll see, too early to tell.

What I can confidently say: error occurs only if memory training happened (code 15).

Will keep posted. For now slowly gathering info.

=======================================================================
BIOS v4.2 so far looks promising:

Did many restarts, restart from UEFI, online power cycle*, and couple offline power cycles**.

BIOS settings all bare-bone default, except: disabled Memory Context Restore and Fast Boot, so it is forced thru "memory training" (code 15).

So far so good, will keep you posted.

=======================================================================
________________
* - "online power cycle" - shutdown PC, power back on.
** - "offline power cycle" - shutdown PC, flip switch on PSU to "0" (so no more even 5VSB to mainboard) - power back on, few times after short time, once after long overnight period.

=======================================================================

Below goes what and how i tested before with older BIOS verisiony, v3.5 and v4.1 which i patched back after figuring v3.5 is not gonna solve the problem.

=======================================================================

BIOS v3.5:

While it seeemed to make a difference, most certainly it wasn't de-facto solution as 4d still appearead.

=======================================================================
BIOS v4.1
For my case, it proved to be quite terrible - but with manual adjustments to ODT, DQ and CA Impedances / Drive strenghts - it was much more reliable.

With manual adjustments, it would fail mostly when memory training was triggered.

Adjustmens (in AMD Overclocking submenu and AMD CBS submenu, NOT in OC-Tweaker section):
- Processor CA Drive streingths: 30 ohm
- Processor ODT Impedance Pull Up P0...P3: 40 ohm
- Processor ODT Impedance Pull Down P0...P3: 40 ohm
- Processor DQ Drive streingths Pull Up P0...P3: 34.3 ohm
- Processor DQ Drive streingths Pull Up P0...P3: 34.3 ohm

- All other BIOS settings default - with those v4.1 would throw 4d ONLY when it would do "long code 15" (memory training) (and then it wouldn't throw it always).
=======================================================================

Will keep you posted.

One more note. Whenver system was up and running, i would do alot of stress testing.
One example:
y-cruncher, zen5 stress test - vt3. Memory occupied by test: >59GB (while using IGPU, of the availble 61.something GB) - it would run for hours..

I also did swap dimm-slots, used single dimm, interchanged dimms. Even with single dimm 4d would occur (v4.1 and v3.5) - but less often.

Main GPU is still out, only one NVME (system drive, in PCIE-5.0 M2 slot) had been left in.

=======================================================================
PS. why is there no "edit" button on forum, previous post by me is a total late-night-written-hafl-asleep mess :)

PS2. When i say "all settings default", it truly means theat, except W_PUMP_FAN and AIO_Fan set to "silent", memory is NOT using any XMP / EXPO, aka memory is @4800MHz.