How to know if a custom ROM uses existing swap partition Recently I switched my custom ROM installed on my HTC Desire to a 4.1.2 based ROM (PARANOIDANDROID based).

The ROM works fine but sometimes the device has serious lag of several seconds. I assume that this may be caused by a SWAP partition I created once on my SD-card but that was never used by my previous ROMs.

How can I find out if the SWAP partition is used or not?
Simply get yourself a terminal app (a good choice would be Android Terminal Emulator), start it, and enter the command free. The output then should look like this:

             total       used       free     shared    buffers
Mem:        487344     474312      13032          0      42224
-/+ buffers:           432088      55256
Swap:             0          0         0


This example is from my Motorola Milestone 2, and you can see: it does not use any swap: "total" available swap space is "0". If your device would use swap, at least the numbers for "totals" and one of "used" or "free" should be &gt; 0.