Comment 2 for bug 1075619

Interesting, I just asked about this on AskUbuntu but I tihnk I figured out the issue.

/proc/meminfo reports the same memory info that landscape-sysinfo does.

Here's the thing, 'free' reports a lot of memory info. To get the data supplied by 'free' to match both landscape-sysinfo and /proc/meminfo, the calculation is:

(used - [-/+ buffers/cache]) / total

the -/+ buffers/cache value is the one right below 'used'

Now your % free should match what is reported by landscape-sysinfo