You can try to install "Bibbers fixed launchers" to run the game in windowed mode through Origin. By the looks of your hardware there should not be any reason for lag. It will be interesting to hear if window mode resolves it.
Ok, now I have tried with Bibbers Fixed Launchers and run the game through that and even there it laggs in those areas where I've mentioned earlier. Despite no reason to lagg it still does. There is now static background but when I go into the game lobby the FPS drop falls down to 8-9 and then back up to 32 fps and then back down every 1-2 seconds...