OMEN X Memory Upgrade and Channels

[HawkeEye]

I have been researching any and every conflict that might exist on my OMEN X and ran into an interesting discovery.  At some point I upgraded the memory, I think, but I have a number of systems and I might have ordered it with 64 gig of memory.  But my problem is the same with either scenario.  I have four 16 gig memory DIMMs making up the 64 gig.  According to the manual the memory can be up to four DDR4 UDIMM 2666.  This is the i9-7920X with 12 cores, so it should be able to handle anything that comes its way.

I ran the HWiNFO64 app against the hardware and discovered that the motherboard is only using 2 of the 4 available memory channels.  I assume this is a mismatch of channel capacity between the four memory DIMMs.  I don't mind purchasing replacement matched quad channel DIMMs if that is the answer, but the world of memory and DIMMs vs UDIMMs, dual vs quad channel, and other nuances makes this tough.

So the question is what memory should I buy to absolutely maximize the capability of the PC?

[HawkeEye]

Since I posted this I continued to research and found a set of 4 UDIMMs by Crucial (CT4K16G4DFD8266) that is available at NewEgg and Amazon.  These seem to fit the specifications, but I  would like some confirmation from someone who is more knowledgeable.  A search on that part number brings up several options.