These are the outboard speakers, not the little tiny, tinny speaker hidden inside the bowels of your computer. Sound cards come in all degrees of sophistication and prices. You more or less get what you pay for, but with a diminishing return as you go up the scale. Where the monitor plugs into the back of the computer is where the video card is located. The faster the card and the more built in memory it has on it the faster your computer processes certain data.
Graphics especially benefit from a fast video card.
Again more is better here. Now we come to the device that is going to get you on the internet and let you hook up to the world. Modem stands for modulate, demodulate which means it is a converter of 1s and 0s to a sound type language that can travel over regular telephone lines, the ones you talk over. Modems are measured in bytes per second which is sometimes called the baud rate which it isn t exactly, but it is close enough. Speed is the all important thing, to cut down those times waiting for a picture to fill in on your screen.