however last week I took DL out of T4 it was the easiest flight I have ever taken the terminal was almost empty security took 3mins thats after a check-in the same time
You have been lucky.
Took KL out of T4, arrived at the terminal 45 minutes before the flight having already checked in via internet.
One minute to drop the baggage.
Then queue....and queue...and queue....until I heard my name being called, the last passenger to board the flight.
I do not know whether the Qantas A380 next to us was the reason of this long queue and huge amount of people through security, maybe yes....
The queue this morning at T3 (SK to OSL) was "normal". It did not take too long. But in OSL the queue at Passport control made me to miss the connecting flight.
I am looking forward to Wednesday at T2 (AZ to FCO).
Ciao
Ulxima