This should fix any latency problems you have over a LAN or Minilogin (Locally Hosting)
a) Open up your EverQuest directory. (Usally either C:\EverQuest\ or C:\Program Files\EverQuest\)
b) Look for a file named DataRate.txt (Should be under 5 bytes in size)
c) Open it up in your favorite text editor (Notepad will do, but if you're a purist, see my title for more information
)
d) Change the number to 10.0, Save, and Exit.