for 500 $ you cannot realistically build a high end system for flight sims imho. best to save more money, otherwise you may end up regretting blowing money on parts that just don't cut it. a MB and CPU alone is alomst 500$ usually, if you pick high end parts i.e. something like ASUS MAXIMUS VII RANGER and Intel Core i7 4790K / 4 Ghz - 8 MB cache If the money burns in your pocket, I would suggest to buy the best MB and CPU for that money and maybe if funds permit 16 or more gb of fast ram, then transfer your current parts, like hdd, gpu etc. Then save up some more and replace the older items that are left.