not very many computers can run FSX with all max settings...
you will be running it decently though with that hardware you proposed. I could give you some tips:
1) that processor should be dual core, and absolutely NOT a celeron. you want the best processor for your money, its the cores that matter now, not processor speed.
2) you'll be wanting something in the upper 8 series cards by nVIDIA. SLi if you really want to let loose. 512 is good. if you can, get a lower level 8800GT, those can get about 320MD vRAM and you'll need every inch.
3) some nice, speedy RAM will help you too, and 4GB is perfect for any system. albeit a little pricy...you'll be wanting a decent bus rate too, PC4200, PC6400, but be warned, with faster bus rates, comes more coin per megabyte.
The settings that are defaulted for your system when you start FSX are the best ones for your configuration. there is an option in the settings menu that says "Target frames per second" set that to about 50 or 60 and you'll be cruising at 1024X768, be ready to turn down the settings at a higher resolution!
good luck with the system, I hope it's what you want!
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