At cruise altitude in 752 v2 in default scenery over Alabama all of a sudden my fps goes down to 10-15 fps and then later it goes back to 60 and then a couple of seconds later it goes down again. Anybody know what's going on?

It is possible that as you are flying, passing over heavily congested areas can bring the fps down.  I just purchased the JarDesigns A320 last night and took a short flight from KLAX to KSFO.  While at KLAX, my fps count was around 20, but after takeoff and leaving the LA area, the count went up to 30.  As I approached the SF area, the fps dropped back down to 20, BUT no crashes.  So as I said, flying over heavily populated areas can cause fps to drop, not to mention that while flying complex aircraft, that too can have an effect.

 

I'm no expert at all the intricacies of XP, but seeing as though I fought the fps issue a lot in P3D and FSX, this was a sticking point when I moved to XP and I watched that counter a lot.  The positive side to XP though is that you can treat it like P3D in that, even if the fps drops, you should still have a relatively smooth running sim and that should be what matters most. 

Life is slower in Alabama.......Former 'Bamian here.

It was the ai aircraft. When I turned them off everything was back to normal. Usually ai traffic doesn't have an impact on my performance

AI aircraft and traffic will have a massive impact on fps.