press escape, options, scroll down until you see arriva name or something like that, and click don't show. That turns it off.
And I don't get much lag at all, and I'm playing on a laptop, with several other large MMO's on it... I think it might just be where you are hanging out. Every one does seem to stick to certain places, just lagging up those spots. Try to avoid large crowds of characters and your lag should get better. The centre of bonfire island, the cave at the entrance to flourite plains, the island where the gate to the Cape is tend to be the most crowded from what I have seen. If you have to go through these areas, just looking away from the other peoples characters tends to fix it...
I wish people wouldn't just sit in the one spot. They don't have to be spread out far, just don't all gather so close together where people have to go through...