Having a fast web site is a dream, and is very essential for good user experience and also is a major factors of SEO and Google ranking. A website that does not Slows Down while opening is much more friendly at first site for the visitor and works until conversion takes place. For instance Amazon as all of us know is one of the biggest on-line stores in the world, did a tests and came to the conclusion which was that a single second delay on page load cost a loss of $ 1.6 billion which lead to drop in conversion rate .
It is important to keep an eye on this . If your site takes a lot of time to load, or is difficult to open quickly you may be missing good visits and conversions.