This little study conducted by Google and Amazon re-confirms what many of us have known for years: Web page visits drop even if the page took a half-second longer to load.
This makes sense when you combine a couple of factors of human nature. One is habit. We people are getting more and more used to instant gratification. Have thought, text message, post to Twitter. Get sudden urge to hear old 80s song again, search YouTube, listen to it. You get the picture. We’re surrounding ourselves by mobile devices of every shape, and it’s just training us to be less and less patient with lag. More on Design For People Who Use Mobile by Slinkysearch.com
Just one more reason to only host your site on a server running Linux (the fastest, most efficient system), and with a local web host so you cut out all the lag you can.