Freeze lag in Raids and Bgs only

I currently have problems when playing in raids or bgs.In major city and dungeons fps is always over 100 but when i enter a bgs(all except arati basin or a raid i run at like 5 fps (latency is normal and sometimes the screen freeze for about 5 seconds or more.This happen to me since monday 9.Suggestions?

edit. Also in arati now...

FAIL (the browser should render some flash content, not this).

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