I made an init.d script, which creates 3 swap files (85 MB each), first in the /system, second in the /data, third in the /cache, and they significantly boost multitasking performance, becuse they're working in parallel mode.
I am using CM 10.1, but I think it it works with all roms.
You have to install busybox 1.20.2 from stericson with the pro app (I can't post it, because it's a paid app), because the other versions can't use swap files in parallel mode (the swapon applet does't have "-p" parameter, to set priorities, so the script exits, and doesn't create swap files), which is the main advantage of this script.
The script set swappiness to 90 ,removes and recreates the swap files at boot, so the boot time increased to 3 mins.
If you delete the "rm .../swap*.img" from the script, it will not deletes the files, so the boot time will be normal.
The matter why I remove, then recreate the files is that they dont't stress the specific part of the eMMC in this way.
Backup your current rom.
Install busybox 1.20.2.
Copy 02Swap2SysDataCache file to /system/etc/init.d folder, and set permissions to 755 (rwxr-xr-x).
Reboot (2,5-3 mins each boot).
You can check swaps with "cat /proc/swaps" command, if they have the same priority, you're done. :-)