It turns out it isn't the case that you can just slap compatible memory in sockets and have the system deal with it.

In what seems like some major PITA, the memory I got to upgrade my AI experiment machine isn't working.

When I installed it, I noticed quickly that the DIMMs were all recognized, and then I moved on. What I failed to notice at the time, but have since, is that the system memory didn't change. I did some quick math, and 4x16GB should give 64GB of RAM, not 32GB, as is shown on the BIOS screen.

I poked on the search tools, and couldn't quite manage the right phrases to get my particular issue to be in a first few pages result. So I started a chat with ASUS, the motherboard manufacturer. I shared the same image, and the tech agreed that looked wrong. He noticed that the BIOS was incredibly old (from 2021), and suggested an upgrade to the latest might fix the problem. I downloaded the latest, blew it out on a USB drive, and headed down to do the upgrade. I went to the EZ Flash tool into the BIOS, selected the BIOS file, and let it run for a few minutes. It said it was done and needed to reboot, so I hit the OK button.

Then I waited for many, many minutes for it to restore. The NIC light was flickering. The fans and motherboard LEDs were on. The mouse was showing its colors, but the keyboard was not. I waited more minutes and nothing changed. Knowing that interrupting firmware flashes is bad, I returned to my Mac and chatted with another person (while I hadn't left the first chat, I timed out waiting for the flash and reboot).

He peeked at the first chat and said that my RAM was actually only compatible in a pair, not two pairs. He gave me a little RAM primer, and I poked around at what he was saying and confirmed the weirdness. He suggested I power off the machine, pull a pair of the sticks, or three, leaving enough to let the machine boot and finish the flash upgrade. Then I could decide what pair to keep and search for different compatible RAM, or buy a ROG board they have that does support my kind of RAM in quads. But that ASUS board is $160! That's only a few dollars more than what I paid for the one I have (which is cheaper now), but that money doesn't count and I have to start over; no longer a $30 upgrade, but a $160 replacement.

I powered off the machine, pulled three sticks, and rebooted leaving the firmware to update in just 16GB of RAM. The machine booted and gave a "firmware upgrade in progress, don't power off" message, so I returned to tell the dude it worked. I went back to the machine and it was waiting for me to let it reboot to finish. While it was rebooting again, I powered it off and added a second RAM stick back, making sure I was using the original pair together. I powered the system on, and discovered it lost the boot settings, so I fixed them, and on the next reboot, the system returned to its old 32GB state.

I'll try to return the now unnecessary memory to the store. I hate returning things, but I'm going to nip the "what can I wrap around this RAM" bug in the bud. I went through their motherboard's compatibility list and searched for all the RAM options that could get me to 64GB or more, but my local store doesn't have any of the compatible options. I can get some of the options online, but I'm not going to do that today. I peeked at their available motherboards, too, and with my new knowledge I also tried to confirm that I could use all four sticks and my CPU on them, but I couldn't see the right stuff that would make me comfortable buying a motherboard to try. G.Skill has a compatibility checker on their site, but it also doesn't let one choose an option like "I want to use 4 of these."

I'm disappointed a little in my lack of understanding this could be a problem and more in the manufacturers of motherboards, RAM, firmware, or whatever, that this is a problem. Clearly the systems can be made to support this, as the same manufacturer's other motherboard does, with the same chipsets, but likely different firmware and wiring.