Matt Cutts, who provides software engineering for Google, answers a question posed by Deepesh of New York. Deepesh wants to know how website load times affect search engine rankings.
The load time of a site refers to how long it takes for all parts of the site to load fully for the viewer, including all text, graphics, video and animation. Having a lot to load, especially video and animation content can make sites load slowly.

In his video response to the question, Matt says that as a general rule, site load times won’t affect search engine rankings. However, some sites load so slowly that even the Google algorithm bots can’t detect the words and phrases used for the title or description of the site. In that case, the slowness of loading the site will negatively affect search engine rankings. Essentially, the site appears to time out to a bot when it takes 30 seconds or more to load. However, a site that takes an extra two seconds to load and doesn’t nearly approach the 30 second mark won’t experience a change in ranking because of the load time.