As a general rule of thumb with all computer hardware, buy the most computer you can afford because it won't be worth squat once you unpack it from the box. Unless you are sitting around all day doing benchmark testing, you aren't going to notice any difference between the hardware you are referring to. Get a good graphics card and whatever other hardware you need to connect your existing peripherals, and the rest is moot for gaming. You can add more RAM and bigger hard drives later if you come up short. RAM and hard drives are cheap.

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