Why does developer tools have a different server response time to a profiler? : I have enabled a PHP profiler, well magento, but it is still a profiler.

The results show pretty decent server response times, but on the chrome developer tools the time is much higher.

Profiler:

[![magento-profiler-server-response][1]][1]

Developer tools:

[![TTFB-chrome-developer-tools][2]][2]


  [1]: http://i.stack.imgur.com/13kag.png
  [2]: http://i.stack.imgur.com/ltfPC.png