Programmer Humor

Yes, it's basically faster than disk swap but uses some CPU cycles. The compression algorithms involved are very fast on modern CPUs so in some sense it's "free RAM".

I set mine to almost 1:1 my physical RAM, because the way it works is that the zram disk size (62.6G there) is the amount of uncompressed data allowed on it, and the compression on real-world data is almost always at least 50% -- so if the zram device fills up, it'll be using something like 32G of physical memory. I'm yet to hit real-world usecases that would have tested these limits though, and the defaults are much more conservative.