Bad performance (Low FPS) with World Update 3 and new London photogrammetry - possible memory leaks

How long are your flights when you normally notice these drops? I flew from KATL to KJFK and had almost no issues even when touching down @JFK down to taxiing it was really smooth and I am not running no high end rig. There was a few minor stutters once I got airborne out of KATL but eventually smoothed out.
What planes are you flying when this occur? I am running no modded aircraft like FBW or SS 747.Those are performance hogs.