If you have never heard of external video cards, you are not alone. This new concept is only recently becoming common knowledge. Video cards, also called graphics cards, graphics accelerators, and other names, normally sit snugly inside the computer case. The purpose of video cards is to interpret the graphics signals from the computer and display them on a monitor. New external graphics cards are being developed, and there are good reasons why they must exist outside the computer's case.
Specialty 3D graphics accelerator cards have grown very powerful over the past several years. They are essentially graphics computers tucked inside the computer case. These internal video cards perform the highly intensive graphics calculations for games and graphics editing, leaving the main CPU to do other work. Some of these graphics cards have grown so powerful that they are more powerful than some of the early computers! Unfortunately this means that 3D graphics cards need lots of power, lots of room, and lots of cooling fans.
One solution is to move the next generation of massive video cards outside the computer case as external graphics cards. These external cards would sit outside the case in their own enclosure, much like an external hard drive. The external video enclosure would have its own power supply and cooling fan. This would greatly decrease the strain on the computer's power supply, and also remove a great deal of heat from the computer case. The external video card would enable many computer users to upgrade to the hottest graphics card without buying a new computer. An extra bonus is that laptop users should be able to connect their same external video card to their portable and use it to boost the video performance.
These external graphics cards are expected to connect to the computer via the PCI External or PCIe specification. Video cards inside the case have a direct connection to the motherboard. External video accelerators would need to connect via a cable. External components have traditionally been slower due to limitations of cable data transfer rates. If that problem can be solved, expect a whole range of awesome external video cards to enter the market soon.