Arena issues (warsong)

[Cudibas]

Hi everyone,
I'm back in the game after a few months break. Everytime I join arenas Lag goes up to 350 ms and my game becomes jerky, not fluid at all, making it impossible to play.
I've never had these problems before the break, and they occur only in arenas (bgs and other environments are totally fine).
Said that I'm not downloading (and stuff like that), that my graphics are set on "low", what can I do?
Thanks for your help :-)

[Cudibas]

Bump I need help please