Just a quick fyi, I am currently building a test workstation using a Supermicro X11SAT board (the no-IPMI version) and I am successfully using 4x 16 GB Kingston KVR24E17D8/16MA ECC UDIMMs. CPU so far is a Celeron G3900, because the E3 1275 V6 was not available a few weeks ago (buying one soon) and because the board came with BIOS 1.0a whereas Kaby Lake needs 2.0+. Upgraded to 2.0a using this CPU, worked. RAM ist driven nicely at 2133 with CAS 15 which is the maximum possible on that 30 buck cpu.
AFAIK there are only two chip manufacturers of such unbuffered ECC memory left, SK Hynix and Samsung, both south korean. It would be very curious if Supermicro did not support all those memory chips, no matter if the modules were made by Kingston, Corsair or whoever.
Also of note, if you install Linux and ethernet does not show up, check for EEPROM corruption on the Intel ethernet chips. Fixable using bootutil on the FreeDOS disk you used to flash upgrade the board. Windows on the other hand seems to just ignore it and bring up the device.