• PCI slots let you connect certain types of cards to your computer. It's worth noting that the PCI standard has been surpassed entirely in speed by PCI-E. Even though they're close to extinction, PCI slots still have a few uses. The cards that are still being produced for PCI are cheap and the installation is a snap--literally.
  
  

Graphics Card

• A graphics card, also referred to as a "video card," is the dedicated graphics processor responsible for the image quality you receive on your monitor. Onboard motherboard video is sufficient enough for casual computer users. For those who like the play 3D games, having a graphics card will produce a better image, speed and performance. As technology continues to improve, only low-end graphics cards are being produced for PCI slots.
  
  

Sound Card

• A sound card, also referred to as an "audio card," is a dedicated sound device that manages the incoming or outgoing sound of your computer. While most motherboards now come with onboard audio, dedicated sound cards are known to produce better quality sound and performance when playing video games, DVDs or anything that is capable of producing 5.1+ audio output. Sound cards also allow recording of audio from microphones and musical instruments.
  
  

Capture Card

• A capture card, also referred to as a "TV tuner," can record audio and video from any device that has video inputs. This includes TVs, DVD players and camcorders. The recorded video is saved on your computer's hard drive, and can then be edited and/or uploaded online. Capture cards can also act as a digital video recorder, allowing you to record, rewind and pause live TV.