Here’s the interesting part. This motherboard doesn’t officially support 16 GB of RAM. The specs on the page I linked indicate that it supports a maximum of 8 GB. It only has 2 slots, so I had a suspicion that 8 GB sticks just weren’t as common back when this motherboard first came out. I decided to try anyway. In a lot of cases, motherboards do support more RAM than the manufacturer officially claims to support.
I made sure the BIOS was completely updated (version 946F1P06) and put in my two 8 gig sticks. Then, I booted it up into my Ubuntu 16.04 install and everything worked perfectly. I decided that my theory about the motherboard actually supporting more RAM than the documentation claimed was correct and forgot about it. I enjoyed having all the extra RAM to work with and was happy that my gamble paid off.
Then, a few months later, I tried to boot into Windows 10. I mostly use this computer in Linux. I only occasionally need to boot into Windows to check something out. That’s when the fun really started.
A deeply technical exploration into this particular issue, and definitely worth a read.