Well, any intel duo core would do it. Even if you did see a bottleneck, all you would need to do is OC tiny bit to up the clock speed. Even the 7500 is good. If you do see a bottle neck as I said just OC it bit No biggy, plus those Core 2 Duo Intel chips are pretty easy to OC.
because i have dual core e2180 and i dont have enough money t change mobo and cpu so the best i can do is change the cpu thats why i wanted to know if an e8400 would be significally better than the e2180