You are stating full memory used, not the real amount used by OS and applications. The full amount includes buffers and disk cache. For example, here in a 160 MB virtual machine, VL 5.8 boots to XFCE with: used=52MB, buffers=6MB and cache=89MB, for a total of 152MB (I know, the sum gives 148MB, but that's the total given in htop and free, for some reason). The used amount (or maybe used + buffers) is what you need to compare, since disk cache is variable. As I got these figures in htop, this means I already had to run a console + htop inside XFCE. BTW, this is practically a vanilla install, and sshd was running.