The only thing that might have an effect on stuttering, that is related to our products, is the "Anti pop-up" setting in the Addon Manager. At its default value of 1, you'll have the best fps and lower memory consumption.
Raising it to higher values, you'll trade fps and memory usage, for less stuttering. At the highest setting, all the scenery will be loaded at once from a distance of about 10NM, and never be discarded again unless you exit from that area. This will consume maximum amount of memory but should fix any stuttering.
If you still stuttering, even after changing that settings, then it's nothing related to any of our products, and it becomes then a problem with your FSX graphic settings (or tweaks, the Bufferpools settings might be the most relevant here) and/or other conflicting sceneries in the area.