Relationship between DNS requests and server's CPU load

Hi, I want to know, is there any research or analysis on relationship between DNS server load ( e.g. CPU load, Memory utilized) and incoming DNS resolution requests ? Besides those research on name system architecture and cache policy, is there any guideline on planing or optimizing domain name service system ? thanks in advance. Joe Cool Things Happen When Mac Users Meet! Join the community in Boston this July: www.macworldexpo.com