I read this on Guild Wars Guru, didn't think it'd make a difference, but it does.
After launching the program, go to the Task Manager, find the process (GW.EXE, should be thing program using the most memory), and set it's affinity to only 1 core.
My ping times went from 250-1000 to 125-250, and frame rates actualy stoped dipping below 60 on occasion (Woho! No more 56 PFS!
)
It may not help for everyone, but it made a difference for me. Shame you have to do that every time.
