I was going to entitle this “you need a faster site” but it makes more sense to say “you WANT a faster site”. Why you ask? Of course there are the typical reasons of making sure you do not lose your visitors due to slow page time, but now it may effect your search results.
Google Site Performance
Google now has a tab in the webmaster tools to view your site performance. Look under the “Labs” section within the webmaster tools and you will find “Site performance”. This information not only details the page load time for your site but also shows additional information about specific URLs.
The site performance tool highlights some of your pages showing the URL, size of the page, total requests and DNS lookups. More importantly these details are broken down into the individual elements. Finally they provide recommendations you can implement to improve individual page performance and overall site performance.
Effect Search Engine Rank?
Honestly I do not know, however a faster site overall cannot be a bad thing.