title: 'ps' and 'top' show different memory usage for single process
body: <p>When I do 'ps -auxwww', it shows X using about 342M of memory. </p>
  
  <pre><code>USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND 
  [...] 
  root      2009  1.0  5.1 342564 105012 tty7    Rs+  Oct08 469:24 X :0 
  [...] 
  </code></pre>
  
  <p>However, 'top' shows about 1358M: </p>
  
  <pre><code>  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND 
  [...] 
   2009 root      20   0 1358m 102m  14m S  0.3  5.1 469:24.27 X 
  [...] 
  </code></pre>
  
  <p>Why, and which one is correct? </p>
  
  <p>I've seen posts re 'top' and 'ps' "total memory used" being different 
  (because of shared memory), but not why this would happen on a single 
  process. </p>
  
  <p>EDIT: it turns out that even none of the "ps -eo" options will give what top gives.</p>