When it comes to CFS2, FS9, and FSX if you want higher performance CPU power is key here. If you want better eye candy your Video card is most important here, and if you want a smoother running experience more system RAM is needed.
FSX is the only M$ simulator currently that takes advantage of a dual core CPU, but it will not fully utilize a quad core CPU. (though some people say they do see a difference when running FSX on a quad)
FS9 and CFS2 were both designed for the single core CPU. So if you have a 2.0GHZ single core and a 2.0GHZ dual core, and they have similar socket design (like an AMD 3200 and an Operton 170) and your running FS9 or CFS2, there will be no performance increase, because both programs are only useing one core and the core's clock speed is the same.
When it comes to eye candy, and this does effect performance as well, a better videocard, or GPU (graphics processing unit) is desired. A better GPU allows you to turn up the eye candy more and add more AA and AF to improve the appearance. The GPU also take a great portion of the image rendering process off of the CPU, which could also improve performance. (but no as much as upgrading to a faster CPU)
Out of the two you selected I would probably go with a 9600GT. It has a lower power consumption then the 9800GT, and isn't that far off from it in performance, plus it has double the video card ram so you will be able to play these simulators at higher monitor resolutions with out take as much of a performance hit as you would if you were to go with a 9800GT. Both cards blow you current GPU out of the water.
Now if your experiencing a lot of stutters or your performance goes up and down a lot, more ram always helps. Having more system memory will not increase your top frame rate much, but it will increase your over all performance because it will allow your system to 'spread out' the calculations more. For example, lets say you have 1GB of system memory. Hypatheticaly speaking lets say your highest FPS is 60 and your lowest is 24 and your average is say 35. Now lets double your system memory to 2GB. Your highest FPS will probably still be 60 (could go a little higher to 62-63, maybe) but your lowest FPS could be up to 28 and your average could now be 38-40FPS. More system memory adds more performance stability.
Hope this helps!:wave:
