I just returned 2 ASRock X399 Professional Gaming boards along with 2 AMD Ryzen Threadripper 2950X because no matter what I tried I could not get the motherboards to recognize ECC, UDIMM Crucial memory (https://www.crucial.com/usa/en/ct16g4xfd8266, 64GB, 4x16, ECC, UDIMM, CT16G4XFD8266, Crucial 16GB DDR4-2666 VLP ECC UDIMM). Both motherboards and processors were brand new. The motherboards were running BIOS version 3.5P. I tried the following:
- Re-seating the processor
- Swapping processors
- Clearing CMOS
- Removing and Re-installing the CMOS battery
- Flashing BIOS again
- Re-seating all memory
- Trying different compatible crucial DIMMs that work in other boards
No matter what I did I could not get A1 & A2 slots to be recognized in bios. The boards would recognize the same memory in all other slots. This is very strange. It is especially strange that 2 boards in a row have this issue.
ASROCK support told me that this is probably a board issue and had nothing else to suggest. I asked as to whether if given a serial number, there is a way to determine if the boards were part of some bad batch. The answer was no.
Am I doing something wrong here? Did anyone else experience this sort of issue? I really like the x399 Fata1ty board because it has the 10GB NIC. But now I am pretty anxious about ordering more parts.