I keep hearing the recommented ammount of swap space for Linux is somewhere around 2 x the RAM. Now... if you have 128 Mb RAM you need 256 Mb swap. But this makes little sense... What if I have 1 Gb, 2 Gb, do I need 2-4 Gb of swap? Or is Linux hardwired to use the swap related to the ammount of RAM.

BTW, I have 512 Mb RAM and use 500 Mb of swap. Is that sensible? So far it's worked, but do I have to increase it? I haven't run any memory-intensive applications (generally because these are 3d games and these are hard to find for Linux).

The 2xRAM rule-of-thumb was a popular guideline when most systems had much less RAM than is now the case. Large swap partitions >500MB now are mostly useful for systems used for editing large images, video files, etc., and large compiles and other memory-intensive tasks. Busy file or database servers might also benefit from quicker reads from swap than from data spread around the drive.

use as much swap as needed, its a slow substitute for RAM ... i use 1gb of swap (i have lots of disk space), but, with 512mb RAM, i don't think i ever see swap get past half filled at most (only time was when a program ran that ate all memory ..... trying to load pcm (audio) data in memory, stupid program, i don't have a few gig of memory to spare!!)