What you're asking simply doesn't make any sense. Dolphin is a CPU intensive application because it is emulating something. If you want to make it use less CPU, turn the frame limiter down to 5 or something.
But, that's not what you're really wanting. You want the emulator to run faster. Unfortunately, even with optimizations that have come recently, I'm fairly sure your CPU will never run a majority of the games at playable speeds. It's not a matter of optimizing Dolphin; it's a matter of your CPU being completely unequipped for using the emulator.
One the bright side, your computer is probably fast enough for most SNES emulators.
But, that's not what you're really wanting. You want the emulator to run faster. Unfortunately, even with optimizations that have come recently, I'm fairly sure your CPU will never run a majority of the games at playable speeds. It's not a matter of optimizing Dolphin; it's a matter of your CPU being completely unequipped for using the emulator.
One the bright side, your computer is probably fast enough for most SNES emulators.