Game freezes In arena Only.

Hello. So Ive leveled up a warlock from 1-80, done some bg, dungeons etc and Ive never had any freeze lag issues until I played arena tonight.
During preparation its fine but as soon as the doors open my game starts freezing. Its not fps drops ( if I check the fps counter I have between 140-200 fps) yet the game freezes every second or two. Once im dead its getting better and when I leave the arena its fine.

I have tried turning off most settings (but due to the hour long queue not those that require a client restart) and Ive tried without any addons. Neither made any difference.
Im using the old client.

any help would be greatly appriciated

Best regards Mwmwmwmwmwm.