My friend has an old Macbook that doesn't have much RAM. I am mostly a Linux person, and I don't know that much about Mac, though I did grow up using older ones. I know that on Linux, it is possible to make a system with less RAM faster by installing zRAM, which overrides the swap going to the hard drive in favor of merely compressing memory that isn't being used at present. I know Mac has Kernel Extensions available. This tells me that it might be possible to install zRAM on a Mac. After some googling around, I couldn't find any software. I was wondering if any of you guys knew any safe Kernel Extensions that enable zRAM. For reference, both my friend's Mac and the Mac I will test it on to verify that it works are running High Sierra.
I can't find a zram app for the mac but there are sites with info on speeding up the ram by adjusting the swapping actions of a mac. This site talks about the same topics you refer to and how to change the swapping for RAM space and how to speed up the performace of your mac.
What Mac does your friend have? It may be possible to upgrade the ram in that machine. Some Macs can be upgraded to twice the max amount given by Apple.
Here is a paper which describes the advantages of compressed memory over swapping. And here is an article talking about compressed ram in a mac. it sounds like the Mac already does what Zram reported to do. You can probablty tell by reading the article yourself.