I would just like to see the price come crashing down on the 8GB modules. 4x8GB is plenty for 99% of home users. 32GB module is insane on an 8 slot board thats 256GB of ram. I guess a few people could utilize a huge ram disk and do all their video editing and rendering directly inside the ram

haha most people can hardly justify having 8GB, though I'm sure I'm going to get a lot of flak for that. But yeah, RAM disks are what I had in mind too. I personally would love to do a RAM disk for a virtual machine, where for probably the first time ever, the CPU would be the bottleneck of the boot process. Of course, that depends on the OS and what you do to it. For example, Windows by default only boots using I think 1 CPU core, but you can tell it to use more through msconfig. If you use sysvinit in linux, it runs the startup processes 1 at a time, but through systemd you get some nice multitasking. It's interesting to me to see what slows down a boot process besides disk load and network establishment.

Are any of the current consumer DDR4 modules built on the 20nm fab?

Nope iirc they are all done on 30nm at present