@lma For most, (me including), ramzswap works OK, but doesn't offer any noticeable benefits.
ramzswp does work on the N900, albeit with questionable benefits. I tried a disksize of 64MB, and ended up with massive swap episodes (bigger than the usual ones, and usually resulting in omap-wd rebooting the device) with just the music player and MicroB running. Perhaps more investigation into kernel tunables may be needed, if it really does benefit low-memory devices trying to run full Linux desktops.