Most recently ADATA has surfaced with new 32GB DDR4-2666 UDIMM memory.
It would make me ecstatic to be able to install 4 of these into X470 box.
I think getting 32gb DDR-3600 would benefit you much more than having 128gb of DDR2666 memory. Past 16gb you will get marginal to no benefit of increasing memory capacity unless you have a very specific need for it. Memory speed on the other hand is directly proportional to performance increase, especially on Ryzen CPU's.
I have seen faster memory at pretty insane prices. For what amounts to a negligible amount of performance gain.
Right now 128GB is till a tad expensive but prices will fall as time grinds onward.
ive got 32GB 16x2 GSkill DDR3600 at newegg for $140 on sale. would't call it insane as a price. and i tested that memory set at both 3200 and 3600 and performance gain overall is about 3%-5%.
8GB and 16GB sticks have come down a lot since introduction
Lower capacity sticks do offer faster speeds but RAM is a lot faster generally over even Optane let along a SSD.
I have believed in the idea, "Cram it with RAM"
back in 1970 a point and click user interface using a mouse was demonstrated on an IBM mainframe. innovation was hardly a recent phenonon