No matter what OS your DNS queries and the time it takes to get the results has a dramtatic imapct on your computers performance when doing anything Network related. Google knows this and they have a need to serve you ads as fast as possible. Which is why they released their own free DNS service to compete with a rather crowded field of free/open DNS services. But which of these is really the fastest? Luckily for us they have an app for that. Google that is. A developer at Google wrote an application called Namebench. It's available for Linux, Mac OSX and Windows. It's super simple to run and turns out graphs and text like this pop-up page
While your results will likely vary from mine the faster your DNS is the faster you can surf.