Nether Lag

1. The Nether lags a lot. I've noticed that anytime I visit the nether, after a while my game starts to lag. Mobs stop moving although they still produce sound and their animations still play (eg endermen still swing their arms), Fired arrows freeze midair and arrows with the flame enchantment continue to burn while frozen midair, lava damage does not register immediately and broken blocks do not drop themselves. The lag lasts for about 7 seconds then moving entities movie in a rushed manner as if to catch up with the time they've lost. Only the player can move whilst all this is happening .This only happens in the nether, the overworld and the end are just fine.