Why is melee so laggy for me?

[Kurausukun]

First of all, as OatmealDome suggested, definitely try the latest dev revision and see how it goes. But other than that, it's a well-known fact that AMD CPUs are very bad for Dolphin compared to Intel CPUs of the same clock speed. I'm no expert, but I think yours should be powerful enough to run a lightweight game like Melee (although is is only dual-core). Other than that, what are your graphics settings?