fps drop after level d install

It appears to me that my fps has dropped since I installed the level d 767. I have the pmdg ngx,super 80, fsdt airports and rex installed in fsx. It appears my fps has dropped and or is more erratic. Is this possible or is it just in my head ? ( I had lots of problems getting the level d to work in fsx) My system is a 2600k oc 4.4 nividia 570. I would like to avoid doing a complete reinstall of fsx.