XFCE:
total used free shared buffers cached
Mem: 506756 362468 144288 6568 22756 179264
-/+ buffers/cache: 160448 346308
Swap: 392188 0 392188
GNOME:
total used free shared buffers cached
Mem: 506756 500360 6396 1948 840 37724
-/+ buffers/cache: 461796 44960
Swap: 392188 66672 325516
LXDE:
total used free shared buffers cached
Mem: 506756 316504 190252 8500 18920 149812
-/+ buffers/cache: 147772 358984
Swap: 392188 0 392188
KDE:
total used free shared buffers cached
Mem: 506756 499724 7032 6772 10516 109760
-/+ buffers/cache: 379448 127308
Swap: 392188 21632 370556
As default using the latest mini.iso with mirror/udeb/suite=sid and using
the 'alternate desktop menu'
booted, logged in, loaded a terminal, here you go. notice the swap usage.
virtualbox vm 512MB