Taking your suggestion I looked for 32GB modules listed on 5820 benchmarks. I didn't find a good way to filter, so I just looked at a bunch of benchmark pages and looked on each for 32GB ram modules and made a list. I did not go through all 5820 benchmarks on Userbenchmark, and I think I was looking a list showing faster benchmark results first, so results may be more represented by w 2200 series CPUs than the average on the site. Pleased to see the M393A4K40CB2-CTD I ordered on this list. And while some similar Hynix modules to my Hynix HMA84GR7AFR4N-VK TF modules that didn't work are on the list, the exact modules I am returning are not to be found. Maybe mine are just a bit older than the ones that work, mine being AFRAN, while the ones listed are AJR4N, CJR4N, DJR4N. Here's what I found: W 2200 Series CPU
Maybe I'm looking right past it, but I can not find any list/QVL of tested/validated/compatible memory modules for my Precision 5820. I got it with four SK/Hynix 8GB 2666mhz DDR4 low voltage CL19 ECC modules, which work just fine. And not finding a QVL or list of any sort, I just got four more of pretty much the exact same thing, but denser 32GB modules with the same or very similar chips, but just more of them on each module. Same maker, same specs, just denser modules.But all I get is a black screen, 3 loud beeps and a steady white power light. I see the list of power light (yellow and/or white) codes in the User Manual for the 5820, but I see no reference to the beeps in the manual. And steady white is supposedly proper functioning. I left it on for a long time, just to see, because if it was doing some kind of POST memory test, 160GB of memory is a lot to test! But after about 10 or so minutes the fans start to slowly crank up louder and louder and that indicates heat and that doesn't feel right to me? Removing the new modules the system boots and runs fine. So, I'd really love to know some 16 or 32GB modules I KNOW are going to work on this machine. Anyone know where I can find a compatible memory list for these machines? 
Validated/compatible memory list for Precision 5820 (Xeon/ECC)???