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And to answer your question you originally asked, you will notice a difference and you won't. As Maziar stated it will depend on what you will do with it. I myself prefer the extra cores, its kind of like having a luxury car with a high performance engine in it you don't normally use unless you just feel like blowing away some red neck in a 1987 mustang gt, lol.

If you have the extra cash and don't mind spending it I would get it and the worse case scenario is you will have a solid chip that will allow you to build another cheap system later if you ever need one...
E8400 is still a very good CPU,if you are mostly gaming then keep your CPU,because in most games with the exception of some RTS games and others like GTA IV,etc your E8400 beats the Q9400,but if you are going to to some renderings then Q9400 would be better
 
And to answer your question you originally asked, you will notice a difference and you won't. As Maziar stated it will depend on what you will do with it. I myself prefer the extra cores, its kind of like having a luxury car with a high performance engine in it you don't normally use unless you just feel like blowing away some red neck in a 1987 mustang gt, lol.

If you have the extra cash and don't mind spending it I would get it and the worse case scenario is you will have a solid chip that will allow you to build another cheap system later if you ever need one...
 
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