If it only occurs at large airports, and the rest of the Sim runs fine, I would suggest reducing the Traffic Density to 20%...or less...or even Zero!
I don't hang about at large Airports so my Traffic Density is set at Zero, and providing the Scenery is Default, I don't have any "stutter" problems.
With my complex, Add-on Airport Scenery, I just put up with the occasional "stutter"...no problem...it's a pain I can bear...

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Frame rate
locked at 25 FPS for "smooth" flying...

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Everything else, Maxed!...

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Paul....G-BPLF...FS 2004.... 8-)...!
P.S. ..don't forget to reduce the "Cloud" complexity in Weather Options...Clear Skies are the best!...

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Socket A AMD 2600 MMX 3D now! Thoroughbred (2.1 GHz), nVidia 7800GS 256, 2.3 GB RAM.....

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Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.