Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
I used FSNavigator for many years, like you did, then went on to PlanG, then ventured to FSTramp, I even signed up for one year. Now I see it eating PC resources and I went straight back to PlanG. And with that, I am very happy, just takes a bit of time to get used toDag, I no longer use FSTramp. . .I dropped it after the Developer decided to start charging yearly for the privilege. I had used it every single day from the time it was first released up until I dropped it and I never saw any change in FPS, certainly not the number you're seeing.