AGP - Accelerated Graphics Port:
AGP Technology provides a dedicated, High Speed Graphics Port Interface / Platform Bus Specification from Intel through which large blocks of 3D texture data can be moved between the Computer's Graphics Controller (Display Adapter) and System Memory.
AGP is faster than PCI. PCI has 33MHz / 32 bit PCI Bus & 66MHz / 64 bit PCI Bus Slots both supporting Bus Mastering & IRQ Sharing. Currently only Server MotherBoards have 66MHz / 64 bit PCI Bus Slots. Bus Mastering allows communication to occur between Device & Memory without CPU intervention. CPU accesses to System Memory proceed concurrently with AGP Memory reads by the AGP Graphics Controller. This allows the CPU to perform other essential tasks.
GART Support (Graphics Address Remapping Table) - "During AGP
memory initialization, the OS allocates 4K byte pages of AGP Memory in
main (physical) Memory. These pages are usually discontiguous. However,
the Graphics Controller needs Contiguous Memory. A translation mechanism
called the GART (Graphics Address Remapping Table), makes discontiguous
memory appear as contiguous memory by translating virtual addresses into
physical addresses in main memory through a remapping table."
Only one AGP slot is allowed on AGP equipped MotherBoards. The PCI slot previously used for the Display Adapter can now be used for other PCI Slot Devices. The brown AGP Slot is slightly shorter than the white PCI Slot and is located about an inch farther back. AGP uses a 66MHz / 32-bit Bus architecture. Current Design changes indicate AGP 8x & PCI 2.2 will be replaced with PCI Express. Done! GB - Enjoy!
Note: Chart above quoted with emphasis on AGP Specification & Slot Type. Chart below quoted according to AGP Name & Bandwidth.
Summary Table above quoted from Matrox.
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Web Development, Gill Boyd & Team - Posted 03/23/2003; Updated 08/05/2008