It’s quite a beast, do you have any projects in mind that need the extra RAM?
Nah but was also just posting as Raspbian Arm64 is now a thing with above link, due to 8gb.
Also nolonger Raspbian but RaspiOS
I was looking at a distributed filesystem http://www.xtreemfs.org/ that needs a lot of ram from memory but each Mycroft you add becomes part a singular network drive.
http://www.xtreemfs.org/
Load the full rootfs (probably squashfs formatted) into memory and use systemd mount overlays for /etc /home etcetera as writable onto the SD or USB.
Than your whole OS runs read-only from memory. Can imagine that might give a boost in snappy-ness 
I think that is something like what xtreemfs does as its this sort of blockchain file system but for speed the main co-ordinator holds it or cache in memory.
But 64bit raspberry is now a thing! Which on a Pi4 actually does give perf improves not to be sniffed at.
64bit is not only a thing. 5.4 LTS linux kernel + proper mesa3d is also quite nice now. Combined with 64bit, is something I have compiling seperately as we speak 
Yeah raspbian 64 bit is released that is all I am saying, been a long time in the waiting. Well they are calling it beta but had to have something for 8gb or it was a bit of a joke.