You have to overclock your CPU. The process is different for every motherboard, as it's done through the BIOS.
Assuming you're on Windows XP, you can find out the exact model of your CPU by going to the Control Panel -> Performance and Maintenance and click on System. It should tell you what model it is and what your clock speed is. I still don't know what specific CPU you're using, but it might be too slow to properly play anyway. If it's an old, single core Athlon 64, I don't think it'll perform anywhere near as good as the 3.4GHz the user on the wiki mentions, even if you overclocked it to that speed. His/her CPU is an Intel Core 2 Quad Q9550, which I imagine runs Dolphin a lot faster than any single core Athlon 64.
Assuming you're on Windows XP, you can find out the exact model of your CPU by going to the Control Panel -> Performance and Maintenance and click on System. It should tell you what model it is and what your clock speed is. I still don't know what specific CPU you're using, but it might be too slow to properly play anyway. If it's an old, single core Athlon 64, I don't think it'll perform anywhere near as good as the 3.4GHz the user on the wiki mentions, even if you overclocked it to that speed. His/her CPU is an Intel Core 2 Quad Q9550, which I imagine runs Dolphin a lot faster than any single core Athlon 64.