About a year ago I upgraded my laptop with 8 GB of RAM. I had Windows 8 and 4 GB which wasn't enough in all situations according to the Task Manager. Shortly after the upgrade I switched to Debian 7 as my primary OS. Looking at the memory usage in the System Info program on Debian I always wonder how can the system work for hours with many application opened with just half a GB or at most 1 GB of RAM in use. The confusion comes when I run the
free command. It reports much more memory usage than System Info. At the moment System Info reports 582 MB RAM and 0 MB swap used while running
free -g reports that 2 GB are used:
$ free -g total used free shared buffers cached Mem: 7 2 5 0 0 1 -/+ buffers/cache: 0 7 Swap: 14 0 14
Why do these two report different amounts of memory used? The other thing that bothers me is that I almost never get near to using 4 GB of RAM even when running a virtual Linux machine with VMware. Is there a way to tell the system use more memory and gain performance in some way?