Will this computer run 5 instances of wow

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But the CPU is kinda a overkill you be fine whit a 3ghz dual core

Don't give bad advice. The difference for *5* boxing between just swapping my 3.4GHz dual core E6600 to a *3.0GHz* Q6600 quad core was definitely not "overkill." The gains were substantial moving to more cores at a slower speed. For someone playing a single instance of a non-multithreaded game, yes, a higher core clock is better. But when you're using your computer in a way that all cores can be taken advantage of, get more cores if you don't have to sacrifice too much clock speed.