Ok, here is Matt Cutts talking about load times and how it affects SEO. A 1 second to a 5 second load time probably doesn’t do much at all for ranking, and my studies of this concur. But if you are on a really slow server that is overloaded with sites OR if you are using a dynamically driven site (like php over mysql) on a cloud server and you regularly experience load times over 15 seconds or so, then you are going to have two issues. #1, as Matt describes, the Google Bot may think those pages aren’t literally there so your rankings will drop or you may vanish completely and be 950ed out of all of the pages. And more importantly #2, which is, people will not dare visit your site again! In this day and age of fast computers, nobody would sit there for 15 seconds to wait for a single page to load. They’ll hit BACK and go back to their Google results and find a new site to visit, make their transaction, etc.
When I first learned about this page load time statistic in Google Webmaster Tools about 2 years ago, I knew that this would be an important factor. So, I then researched what would make a web server fast enough to prevent any issues, and embarked on an optimized hosting plan for my clients. I recently took one client’s page load times from 12 seconds, 15 seconds, plus regular TIMEOUTS, down to 3 seconds or less as a typical page load time. See it here: http://www.shopthevu.com I did this by hosting it on our optimized web servers, and added several caching features to this site for all of the images.
Is your page load time killing your rankings?! Let us know, we might be able to help.