128GB 4x32GB DDR4-3200 PC4-25600 2Rx8 ECC Unbuffered Server Memory by NEMIX RAM

These 4 x RAM sticks worked right out of the box. In a QNAP NAS.

UPDATE: Tightened timings. I've been running mine perfectly fine for over a month at DDR4-3600 22-22-22-52-1T 1.35V after passing 4 passes of memtest86+. Basically stock SPD 3200 timings at 3600 at 1.35V (up from stock 1.2V). I may try tightening by 2 again.There isn't really much choice if you need relatively fast DDR4-3200+ ECC UDIMMs for AMD TRX4/TRX40 Threadripper platform, as ECC RDIMMs and RLDIMMs are not supported. 8x 32GB will max out maximum supported TRX4/TRX40 platform capacity of 256GB. These come with default SPD of DDR4-2666 if you boot on Auto DDR4 parameters in your BIOS. You can then increase memory to DDR4-3200 in your BIOS. Make sure to disable XMP/AMP memory profile support in BIOS as mine wouldn't POST with it enabled at DDR4-3200. At DDR4-3200 SPD timings are 22-22-22-52-1T 1.2V. I'm running mine perfectly fine at DDR4-3600 24-24-24-56-1T 1.35V passing 4 passes of memtest86+. I don't recommend going above 1.35V because newer higher-density higher-capacity lower lithography memory cells have lower Vmax and these come with no heat-spreaders. I have super-fast binned Samsung B-die non-ECC 16GB dual-rank DDR4-3200 14-14-14-34-1T 1.35V modules I ran at DDR4-3600 16-17-17-17-1T 1.45V and memtest86+ benches these NEMIX modules 15-20% slower in throughput and 20% higher latency than my super-fast binned Samsung B-die kit at DDR4-3600. I use NEMIX ECC RAM with AMD Threadripper 3970X on workloads that take hours to days to complete and eat up a lot of RAM (currently up to 90GB allocated out of 128GB, my previous 64GB capacity caused heavy memory swapping and SSD thrashing). So far I have no problems with this NEMIX ECC RAM. If you run lengthy workloads that require in excess of 64GB, ECC UDIMMs is a no-brainer requirement.

motherboard is ASUS TUF GAMING B550M-PLUS WIFI IICPU AMD Ryzen 7 5800Xdoes not bootkingston DDR4 ECC (KSM32ES8/16MF) works just fine

Crashing on an asrock rack x470 board, will return

I bought one set and it works great with my Threadripper 1920x in an ASRock Taichi x399, so I got a 2nd set for a total of 8x32GB. All good!I will note that these did NOT work with an ASRock EPYCD8 and 1st gen Epyc, but I don't know that it's the RAM's fault. That board seems to be picky and only likes Crucial.