AGP vs PCI Express??

AGP is short for Accelerated Graphics Port. As the name suggests AGP ports are dedicated to graphics. AGP ports are unique, in that they are the only expansion slot found inside a computer that works for only one purpose. The AGP channel is 32 bits wide and runs at 66Mhz for a total available bandwidth of 133 MBps (Megabytes per second). AGP ports give the graphics card direct access to system memory to speed performance and allows the video card to store data directly in system memory.

PCI (Peripheral Component Interconnect) Express is a scalable I/O (Input/Output) serial bus technology set to replace parallel PCI bus which came standard on motherboards manufactured from the early 1990s through 2004. In the latter part of 2004 PCI Express slots began appearing alongside standard slots, starting a gradual transition.

Intel first introduced PCI technology in 1991 to replace the ISA/EISA bus. It was later taken over by The PCI Special Interest Group (PCI-SIG) who revised the protocol in 1993. Although robust enough to last over a decade, total available bandwidth of just 133 MB/ps shared between slots meant that high demand devices quickly saturated resources. In 1997 this problem was partially alleviated by implementation of a separate AGP slot (Accelerated Graphics Port) with dedicated bandwidth. Other steps were also taken at the chip level along with integrated components, which helped to extend PCI's viability. However, with the advent of SATA, RAID, Gigabyte Ethernet and other high-demand devices, a new architecture was required.

Intel answered with PCI Express, or PCIe for short.