The soundcard is inserted into an expansion slot inside the PC's system unit. It usually outputs around 1 watt to each speaker although amplified speakers can produce much higher levels, typically 4 to 40 watts per speaker. For general use, 10 watts is more tham enough, but if you want to use your computer as a musical instrument, you will spend the same care in choosing your speakers and soundcard as you would buying a hi-fi system.