So, few hours ago i made a run in Canachs Lair, putting aside it was bugged and nothing happened after the fight, the framerate was terrible in the cavern. I recently bought new pc, capable of running wvw at 20 stable fp with all settings on maximum, but in the Canachs Lair i was seeing a slide show. To be precise, slides started when the traps launched their effects. Even without triggered traps it was bloody awful.
Radeon 7970 should handle small room filled with traps, but i guess there is some magic behind it…