At times loading the fleet can lag a little due to the large amount of people, which is more related to HD speed, RAM, or my vid card, still this is due to the increased population though as my PC has to handle more players in a concentrated area. Turning shadows off did help substantially and I was able to keep the other settings high.
Haven't had anything noticeably bad on the leveling planets. Can't speak for FPs or Ops, taking a break from those atm.
LOL BioWare brags about SHADOWS and now we have to turn them off to play the game, FAIL!