Me and sting were doing missions and when we were both fighing at the same time, it became jumpy. This was when there was about 10 players on ( i think ). NPC's do affect the lag in a negative way, but i saw about 10 Xenos slogging it out with 2 Guardians and 3 patriots and all was fine.
Also, before that, i was killing stuff at the bering gate in texas for a guy who wanted loot. On and off there but the swarmers saved me. Came on when transports and escorts came from the lane.
