Domain Name Speed Benchmark

A unique, comprehensive, accurate & free Windows (and Linux/Wine) utility to determine the exact performance of local and remote DNS nameservers . . .

You can't optimize it until you can measure it: 

File stats for: DNSBench

Last Updated: Size: 176k Dec 09, 2009 at 13:03 (6.54 days ago) Downloads/day: 1,648 Total downloads: 49,164 Current Rank: 1 Historical Rank: 1