How much memory is Linux really using?

An htop on my system reveals this:



So you would think that I am using about 4 gigs of Memory.

The “Mem” line is misleading so please do not use that. instead use the following command:

free -m

Pay attention to the -/+ buffers/cache line.

Useful Websites

Linux ate my RAM

Using top more efficiently

Experiments and fun with the Linux disk cache

Clear RAM Memory Cache buffer and Swap Space on Linux