I am currently running 1G Geil DDR500 PC400 RAM on a high end system. Pescott 3.4 X800XT XP SP2. Would there be any benifit to FS9 in adding another 1G DDR Ram of the same RAMThanksAndrew.

1 gig should be fine. I would suggest more memory only if you have lags in view changes, scenery loading or similar indications of slow response. More memory will not give you higher fps. That is a function of the cpu speed itself.Sherm