Post you Dolphin settings, either as plain text or as a screen shot.
Without seeing your settings, my advice is make sure to set "LLE on Thread" is enabled in your DSP settings. Also, note that LLE is more demanding than HLE since it more accurately emulates how an actual GC/Wii DSP would work. You could try an optimized build from the Development forums, like one from Lectrode, DefenderX, or ExtremeDude2. Other than that, overclocking always helps, just keep your temps in check.
Without seeing your settings, my advice is make sure to set "LLE on Thread" is enabled in your DSP settings. Also, note that LLE is more demanding than HLE since it more accurately emulates how an actual GC/Wii DSP would work. You could try an optimized build from the Development forums, like one from Lectrode, DefenderX, or ExtremeDude2. Other than that, overclocking always helps, just keep your temps in check.