Hi Stephen,The Core2Duo is currently the only processor capable of running FSX at an acceptable level with autogen, AI, and sliders pushed right of center. Even then, frame rates reportedly drop into the teens if FSX is not tweaked and settings aren't reduced.The X2 4000+ has a history of overclocking goodness. If your memory is up to the task. you should fare pretty good with that processor. The expense associated with adding another AMD 939 processor wouldn't be very cost efficient if moving to a Core2Duo in the next few months is in the cards.With Vista/DX10 on the near horizon and AMD/ATI designing for both, competition is bound to lower the cost of compatible video cards. On the other hand, if money is no object, the nVidia 8800GTX looks nice and is said to be graphically competent. It's ability to enhance performance in FSX is questionable at best.Patience, at his juncture, is a virtue. Let the hardware, Vista, DX10 and ACES catch up.You should be having no problems with FS9 even when running the PMDG 747 with that setup. I had a much lesser spec'd machine and never has any fps issues with PMDG. Look to updating your motherboard, video, and sound card drivers. Overclock that processor and memory. Tweak the heck out of your FS9.cfg file. I think you'll be happier not chasing the holy grail that doesn't yet exist. Happy HolidaysJim Karn

I agree about the difference. Ive always been happy with my FX-55 processor but finally upgraded the somewhat aging X850 ATI video card for an XFX Nvidia 8800 GTX, just got it in the mail today. WOOOOOOOOOOOOWFS9 is amazing, double the frame rates.Now if only nvidia could fix the bloody airplane display screen being blacked out. how annoying!I took a few months off from flight sim because performance just was so annoying but now it is so smooth!