If you suddenly find that your Internet speed has slowed to a crawl while browsing the net, in all probability it could be because of problems in name resolution. Resolving web address names to their respective IP addresses where websites are hosted, is the job of Domain Name System (DNS) servers. You can now find out the fastest DNS servers for your location using a nice open source utility called Namebench.
Namebench is an open source DNS benchmarking utility. Namebench runs a fair and thorough benchmark using your web browser history, tcpdump output, or standardized datasets in order to provide an individualized recommendation. A series of tests are conducted against all known DNS servers and the fastest among them is recommended for use on your computer.
After Namebench finishes benchmarking the DNS servers, it will present the result in a very user friendly HTML web page. This page will contain the recommended configuration, tested DNS servers and graphs indicating their response times.
Namebench is available for Unix, Linux, Windows, and Mac OS X making it truly cross-platform.