Oh, it wasn't due to the amount of people looting it specifically it was the server response time on extremely high population servers. For example, the celestials would remain at 0% HP for a good 10mins before changing to the next one. It was pretty similar with the chests, I mean you could stand there clicking it with auto loot and nothing would happen. People from other realms were also joining us through CRZ when they acquired the PvP item (forget the name) to kill people which made it infinitely worse >.>. Seems silly that US would have so much better optimization.