Quote Originally Posted by 'softflow',index.php?page=Thread&postID=126334#pos t126334
I'm not sure if this is common knowledge or not, but the US servers are not necessarily located in their 'game time zone.' Here's the list of the US servers by datacenter from the wowwiki:

http://www.wowwiki.com/US_realm_list_by_datacenter

I'm in North Carolina, as you can tell, and my ping to the Seattle servers is around 200ms with this TCP Ack Frequency fix in Vista64. Before, it was around 280ms-300ms. However, my ping to the Dallas servers and sometimes the Boston servers is 40-55ms. I use Quartz for a cast bar as it has the lag built into the casting display (great feature!) and have easily hit 450-500 ms in instances on the Seattle servers, but rarely see it over 100 on the Dallas servers. Quite a difference!!

Check each data center and choose a server based on those results if you're really looking to improve your ping.
Using Quartz or some other in-game measure of latency confounds network issues in getting your packets to/from the server with server load. You'd be better off doing a traceroute. I suspect you will find that the time spent on the extremely fast fiber optic backbone that carries your packets from your local area to either Seattle or Dallas is insignificant. (After all, the speed of light travel time around the world is something like 30 ms.) The real delays happen in the local networks and on the servers.