288-pin ECC is, I believe, available on any X670E/X870E platform boards so long as the motherboard builder hasn’t expressly interfered with it (and probably other chipsets as well?). Windows 10+ reports it as full ECC (multi-bit / 72-bits). AMD pushed that enable in an AGESA three or four years ago iirc. The CAS latency for ECC is about double what gaming RAM offers, but in practice other more costly factors tend to limit performance first. Any motherboard released before the AGESA update would be more difficult to predict, but that’s baseline uncertainty for PCs so no surprises there.

>The CAS latency for ECC is about double what gaming RAM offers

Ironically, overclocking ECC memory is much easier than overclocking non-ECC DIMMs, because you know exactly at which point you start encountering instability and need to dial back, instead of relying on.. application crashes and BSOD's to know that you're running way too optimistic clocks/timings.

Meanwhile I overclocked 'low clock / loose timing' ECC DIMMs on Ryzen 7 platform with no issues at all – kept increasing clocks and lowering timings until ECC started reporting errors, then dialed it back a couple notches, and now it is not just stable, but I also have exact reporting of it being stable.

Yeah! A stick of 5600 can generally reach 6000 with geardown off and that’s as far as I’ve seen cause to dial it. But certain parameters that are popular to lower for latency reduction can be, how would I put it, slightly less flexible — tREFI comes to mind as one that nearly any lowering of (on the enterprise sticks I’m using anyways) tends to cause DFE/MBIST training failures no matter what, even with direct airflow, before it ever boots far enough for memtest to expose ECC errors.

(For those out there following along with PCs, if you aren’t tuning with MBIST maxed out in your BIOS, you might want to revisit that.)

Same experience here. I have a feeling ECC in gaming would soon become a thing if it wasn't for the pricing crisis.