Need some help please, new to dolphin.

[Ltrhino]

I run vista 64bit with dual radeon 4850's and have a amd quad core and im experiencing slow gameplay with Sonic Adventure 2 Battle. Ive been reading on how to fix my issue before posting but i havent been able to find anything. I have the dual core checked and im running the Dolphin Opengl graphics plugin and i just cant get the game to run properly. I tred Direct3d9 and all it did was make things worse the game played so poorly. Ive tried not running sidebar also while using dolphin. I expect this question to alrdy been asked and many attentions spans may be short, but i would be much appreciative towards someone willing to help me. ty