Attaching to the Motherboard Video display cards attach to the computer through one of the computer's buses. Some use the AGP bus, while others use the PCI bus.
Video memory serves several functions.
It must also hold data about 2D and 3D objects so that they can be quickly moved and manipulated independent of the overall background. 2D accelerators are special chips or chipsets that are used to radically increase manipulation of 2D object and images. 2D objects can appear to have three dimensions, but cannot actually be rotated to reveal their sides and back. 2D images might be photos scanned into Photoshop. 2D acceleration is a mature technology, so most cards have 2D accelerators that are sufficient for just about manipulations necessary.