B450M/ac R2.0 PFEH and ECC question

Additional context - While it is specified in the board's manual that only KSM26ED8/16ME (ECC), TE416G26D819-UHA (ECC) for the vermeer, matisse and renoir architectures and CT8G4WFD824A.18FB1 (ECC), AD4E2133W8G15-BHYA (ECC) & M391A1G43EB1-CPBQ (ECC) for pinnacle ridge, raven ridge and summit ridge. At least from what I can see specified on the board's page.

As for the B450M/ac R2.0, I am trying to understand if it's only ECC modules (no ECC mode) or if ECC modules support ECC mode entirely. Deriving from alot of cross referencing I came to the conclusion that any Asrock boards equipped with PFEH can redirect the ECC to the BIOS (controller) or OS directly - partially or fully.

So my questions are as follows:
1. Does the board support full ECC mode (not just physical modules) ?
2. Whilst there are specified modules, from what I've heard, the rule of thumb being same family of RAM equates to full ECC support. Has anyone ever tried that out if they've had the chance?
3. If yes to the above, how does ECC run on windows 10 (Home, Pro and Enterprise), as well as linux (Void, Arch and Debian/Ubuntu) ?

What began as an inquiry on pcpartpicker led me here, given the lack of documentation of ECC on AM4 platforms is very frustrating. Any PRO cpus pair with good RAM, that's a given much less unofficially some others from what I've heard. To that end, I hope to hear anyone willing to share their experience with this board (or similar). I would also be very happy if this thread could serve as a solid reference for future inquiries.

Also props to ECCential, he answered a few of my questions a couple of weeks back. Very helpful and thanks to him!

Happy holidays to all.

Thanks for the reply, eccential.

After looking things over, it seems I originally overlooked the
Level1Techs forums ??if rules permit I'll cross-reference it here.

Regarding QVL and JEDEC: at first I assumed only listed modules were
truly supported because documentation is so sparse. In reality, it?™s
not that manufacturers ?œlimit??compatibility, but that they don?™t
waste time validating every possible DIMM. The QVL ends up being
little more than a reference sheet. Standard unbuffered ECC UDIMMs
from well-known families (Kingston, SK hynix, Micron, etc.) should all
behave correctly as long as they follow JEDEC specifications.

My last stop will be the L1 forums. When I bought my current board,
I knew it was solid, though server motherboard BIOSes tend to be clunkier than
"prosumer" boards. The pricings were also way above my budget.

As for your 8GB DDR3 EUDIMM, it isn't surprising considering it must've been a popular brand. The unusual thing is the 72 bits width.

Out of curiosity, do you have all of the asrock boards you've experience with, listed somewhere on the forums?

I'll also leave a quick summary if anyone ever has the same questions as me:

1. For any board with PFEH we can assume basic ECC functionality (with proper cpu and RAM).

2. QVL is at best a reference paper, any JEDEC compliant DDR4 ECC UDIMMs should do the trick perfectly (no questions asked).

3. Given your experience with asrock motherboards, multi-bit ECC for them all.

Just on a side note, I'm intrigued that all of your boards display multi-bit ECC and not single-bit ECC. Still given it shows multi-bit ECC, I may have scored the jackpot there. In due time, I plan on adding my experiences with the L1 forums and the modules I buy. This should serve as a neat little repertoire for future builds.

Also very important - it remains amusing how pcpartpicker shows ECC on any intel cpu but none on AM4. False information and I don't know why they even bothered implementing it in the first place but just my 2 cents.

Cheers.