newb question, new at this

hello everyone I'm new at OC, and building my own system. I just want to know what are those CAS latency number for? for example 2-3-3-8-1t what are the first 4 digit and that 1t stand for. the small the number the better performance or the opposite??? Also between QVC and A-data, which one has best performance and can OC the highest. btw I'm using socket 754 Amd64 plan using epox or chintech or MSI k8n neo MOBO

thx for help

the sticky in the memory forum is a good place to start and i believe has most of the answers to your questions: http://www.ocforums.com/showthread.php?t=257741

as for a64 info, the amd cpu section is a great place to head for that particular info, but here a couple of helpful links to get ya started: http://www.ocforums.com/showthread.php?t=295328&page=1&pp=30 AND http://www.ocforums.com/showthread.php?t=306418&page=1&pp=30