You should be getting fullspeed even at stock. I have the GPU but an i5-2500K, but both games run pretty much perfectly. Zelda TP + LLE audio + Hyrule Field later on in the game can be quite demanding; either use HLE audio or OC your CPU if possible. If you do use LLE audio, do not put it in a separate thread; it will freeze Dolphin sometimes if you do. Additionally, OpenGL is much faster than D3D9 now; use it an enable the Vertex Streaming Hack (Graphics -> Hacks).
Fwiw, your specs are plenty powerful for these two games. But how is a real Zelda marathon without Four Swords Adventures? :p
Fwiw, your specs are plenty powerful for these two games. But how is a real Zelda marathon without Four Swords Adventures? :p