So it basically makes a fake swap space in your RAM and that section is compressed. Linux still treats it as swap space so it only writes to it when you're low on RAM (or there's better things that could be cached in RAM even when it looks like your RAM is mostly empty it can still cache frequently accessed data from your disk). Zswap tries to store most swap in the compressed section of RAM, but when something doesn't compress well or when there's just too much stuff for RAM, it will write to the swap on disk.

So one would need a huge amount of system RAM to have this work effectively.

No, it's good for all sizes of RAM. If you have really small RAM, Zswap can actually be essential because without it you would be reading/writing to disk swap too much and performance would suffer. Someone got Linux running on a Switch Lite, just 4GB of RAM with full desktop and Steam too, and they said "With only 4 GB of RAM, zswap is basically mandatory here"

I have 32gb RAM and practically never fill it up when playing a game, usually.

Zswap would probably still improve performance for you, but it might not be a noticeable difference. But it will reduce your SSD writes, so that's nice to improve SSD lifetime a bit.

This is a very technical article about zRAM and Zswap https://chrisdown.name/2026/03/24/zswap-vs-zram-when-to-use-what.html (I think his tone is overly harsh on zRAM, zRAM can be great if the computer has a slow spinning rust hard drive)

a little less technical https://easylinuxtipsproject.blogspot.com/p/speed-mint.html#ID2