Will B

So I kind of chuckled a bit when you suggested that but I tried it with all four sticks installed and it posted. However, only 32 GB of the 64 GB installed were being recognized. I restarted and the next time it refused to post. To me, this is indicating a motherboard issue with memory channel A.

It's running a brand new Corsair Hydro H110i. Right you are, my mistake. Let me clarify, because the slot naming is strange. I can post with slots 1 and 3 occupied. These are adjacent slots, different colors, but both are channel B according to the motherboard manual. So it appears I am only able to utilize one channel. The manual says that dual channel mode can be enabled when using two or four modules, a process I would think is automatic. Is this correct thinking or might this be some BIOS setting I missed?

BIOS is up to date already. I verified each DIMM was working as my first trouble shooting step by inserting each into the same slot and getting a post. I have heard many reports from people experiencing system instability with certain pairings of DIMMs and slots so I tried about 6 different configurations of all 4 sticks and numerous combinations of two sticks. I could only get slots 3 and 4 (different channels) to work with two DIMMs, not even slots 1 and 2. The only slot that seemed to like one DIMM was slot 3.

I just put together a new workstation setup this afternoon and ran into a mind-boggling memory problem. I checked compatibility of all these components before purchasing: Gigabyte GA-X170 Extreme ECC Kingston KVR21E15D8/16 ECC (16GB x 4) Xeon 1275 v5 3.5 GHz I checked the QVL for the motherboard and it lists the 8GB version of that Kingston RAM, but not the 16GB. Kingston claims it is compatible on their website, and the specs all match up fine (DDR4, 2133MHz, 2Rx8, 64GB memory maximum). The CPU can handle 64GB and two channels at 2133MHz. The exact error that is occurring is error code 55: memory initialization error. I tried many different combinations of DIMMs in and out and in different positions but the only ones I could get to post were two DIMMs in slots 3 and 4 (different channels). All four are functional, as I tested them individually in my troubleshooting. I found some advice saying to change the memory multiplier to manual at 21.33, which I did. Still couldn't get 4 DIMMs to post. I'm at a loss here. I can survive on 32GB RAM but I got 64 for a reason. Any help would be appreciated. I've done my best to search through all the suggestions on other forums but there is nothing on this board in particular. Thanks in advance, Will.