Lagging/fps drop only in blackrock

I play on all 3 WotLK realms and use the same addons for all of them, but for some unknown reason. I always get massive lag and fps drops only when I play on Blackrock. Specifically, this occurs whenever I enter BGs on my Blackrock char, but everything else works fine.

Has anyone else experienced this or know a possible fix? Would really appreciate it.

I'm getting that too. Insane FPS lag everytime i join an arena match. My PC handles AAA games on ultra graphics and is failed on this old game... makes no sense.