And yet, while I haven't experienced it, others have complained about Google Analytics slowing their site. They would add GA and response time slowed. They removed GA and response time returned to normal. All I can say is -- place your GA call at the bottom of your page. I would also take a look at your site in general. GA could be the proverbial last straw: check your database calls, see if there is inefficient coding, are the graphics optimized, are you using tables for layout.