Steven S. Klug, EverQuest Lead Programmer, has mentioned:
If you have bloom lighting turned on that can slow down some kinds of video cards. Try turning it off in Options->Display->Advanced.
You shouldn't need to turn off post effects as they are only used under certain circumstances. But it may provide a slight boost for some people with old graphics cards (nvidia 5xxx series being the big offenders)..
- Steven S. Klug, EverQuest Lead Programmer