What is the benefit of getting a video card from nVidia or ATI? Which one is better? What about sound cards?

I have nice video and audio from my motherboard now. What would be the use of getting an audio or video card? Which ones are the best?|||by far accellerated grafix

high end gamming shyt

daul moniters\

nvidia is better if ya ask me

if ya dont game ....dont worry about it|||The benefit of having a video card is that the card takes some of the strain from the CPU, so that you can run cooler, and better programs on your computer.

For which one, GET NVIDIA!! nVidia is more reliable, compatible, and better quality for money.

The same thing with sound cards, although its not as necessary, sound cards help speed up your performance when sound is involved with your tasks.|||nvidia is beter thats what i have, sound cards are for sounds the other 2 are for the video or what you will see when you turn on the computer