namebench

The Google Code project namebench (no cap) is an “open-source DNS benchmark utility” for OS X, UNIX, and Windows. It finds the fastest DNS servers for your computer.

If you poke around a bit online, you’ll find a folkloric consensus that Google Public DNS and similar services are faster than an ISP’s DNS. I switched to Google’s DNS in 2009, and the difference in speed was indeed great. But now namebench tells me that my ISP’s DNS is faster. Because more people are now using Google’s DNS? Beats me. At any rate, I’ve switched back. And yes, my ISP’s DNS is faster. PDQ. QED.