Strange frame rate problem with FS9 MD-11

I have been having strange problems lately where in Virtual cockpit view the frame rates are not more than 9FPS and the same with the PMDG 737, and it is not my system as my other add ons get 30 FPS in VC view so this makes me think it might be livery's or something is using a lot of resources, but I don't know what it could be and this has only been happeming with my PMDG aircraft lately and I even did a clean install of FS9 and it still happens. i could use some ideas here. I am running Windows 7 64 bit with a duel cor processor and all other add ons don't experience this issue, so what could it be?Michael Pare