Try to lower the game graphic settings, or make sure you don't have too many kinds of items in your character's inventory. For example, this happened to me when I play New Vegas, if you carry too many kinds of junks, too many special ammos like High Velocity or Incendiary ammo, playing as a Prospector, the game lagged so much. It nearly freezed some point.(seems that my computer isn't so powerful to run this game.)
Problem is that you can't reduce any lag on the consoles exept from removing random shit from your inventory.
If you're on Xbox, try installing the game to your hard drive if you have enough space. That helped me AND reduced loading times between doors.