AM5 ECC support£

Shorting data pins sounds really good robust idea for testing. I would've thought to start overclocking or messing with timings to try to get non-crashing bootable state but at the same time with some errors but this balance is hard to achieve. Bios injection settings have not worked before if I remember correctly that there were some on AM4.

I am using these modules in the Asrock B650E ITX board: KSM48E40BD8KM-32HM. The way I injected errors is really janky and I don't recommend doing it if you don't have steady hands/don't want to risk your hardware. I just took some tweezers and shorted a data pin to ground (287 & 286). I did the same with DDR4, as well as earlier last year to figure out that ECC wasn't working on AM5, so it wasn't too bad. The BIOS seems to have some ECC injection settings, but I have no idea if they work or not. Memtest86 doesn't seem to be updated yet so I can't try it.

Pinout for reference: https://media-www.micron.com/-/media/client/global/documents/products/data-sheet/modules/unbuffered_dimm/ddr5/ddr5_udimm_core.pdf?rev=fdbd9476506c4e019360a5e402827caa

I did some testing with the new BIOS and can confirm ECC is working. https://imgur.com/a/w2jNLNg

Those are all Registered DIMMs. Ryzen won't ever support them.

But I believe we'll end up with 64GB unbuffered DDR5 DIMMs at some point, just as we got 32GB DDR4 DIMMs some time after DDR4 became the major player. Asrock's spec page for X470 Gaming-ITX/ac still says max supported memory is 32GB (16GBx2), but I'm running mine just fine with 32GBx2, so there's that.

Back in the early days of DDR4, the only ECC UDIMMs I could find were 2133MT/s. Nowadays, 3200MT/s is the norm. So I actually want to wait for at least 5200MT/s JEDEC to become the norm for DDR5 ECC UDIMMs before I jump in.

ApplesOfEpicness wrote: Update from the engineer. The fixes are committed for AGESA 1005. They guess it will come out sometime in Feb 2023.

Good to hear, was about to need new PC-s early spring.