Your GPU is good for Dolphin. The GPU is responsible for things like Internal Resolution and anti-aliasing. Your CPU is responsible for much of the rest. The AMD FX 6300 isn't the fastest CPU for Dolphin, but it should handle Melee just fine.
We'll need some screenshots from you. For your settings, click the Config button and look at the General tab, then click on the Graphics button and look at the General, Enhancements, and Hacks tabs. Right-click the game in Dolphin and click on Properties. Lastly, download and run CPU-Z and Core Temp. Take screenshots of these so we can have a clearer idea of what's going on.
We'll need some screenshots from you. For your settings, click the Config button and look at the General tab, then click on the Graphics button and look at the General, Enhancements, and Hacks tabs. Right-click the game in Dolphin and click on Properties. Lastly, download and run CPU-Z and Core Temp. Take screenshots of these so we can have a clearer idea of what's going on.