VLB video cards provided better performance than ISA cards. It offers local bus performance and solves many of the problems associated with VLB, and introduces a host of new features including Plug and Play and bus mastering. The modern PC uses PCI for other adapters also, such as sound cards and modems. AGP addresses bottleneck problems by defining a new interface for video information that quadruples the theoretical bandwidth of current PCI buses. AGP is a port, and not a bus, because a bus can support multiple devices and AGP cannot.
Many video cards contain what is called a feature connector.
This is an additional connector that is used to connect the video card to other video devices such as 3D accelerators, MPEG decoders and video capture cards. The reason that these connectors are used is that they permit the direct transfer of video information from these devices to the video card, without having to use the main system bus. This original feature connector was part of the original VGA specification. This is now an obsolete standard and is not used by higher-end cards. Developed by VESA as an extension to VFC, VAFC widens the port from 8 bits to 16 or 32, and provides improved signaling for more reliability.