zram > zswap. compressing/uncompressing a block device in ram is much faster than doing the same from a block device on disk on virtually any cpu/ram/disk combo. typically you can set it up to use the same size block as your ram max and it works fine; 8gb zram block for 8gb ram for 16gb total ram. it's not gonna be as fast as physical 16gb of course, but is faster than an 8gb zswap block on disk.

you can also use them together, too, and only start putting pages in the slower zswap disk once zram is full. magical stuff.