Speed has been a consistent theme with the company over the past year or so, with the release of various tools and announcements. It has become quite evident that Google places a great deal of importance on speeding up the web. Google recommends that you watch the load times over a short period of time to see what’s stable, because you may see spikes here and there. If you consistently see high load times, that is probably representative of what most people see.
http://www.webpronews.com/topnews/2009/12/14/things-to-consider-if-page-speed-is-to-become-a-ranking-factor