AGP (Accelerated Graphics Port) Video Cards

AGP is an expansion slot developed by Intel to be used for video cards. AGP is based on PCI, but insted of using the PCI bus for graphics data, AGP introduced a dedicated point-to-point channel so that the graphics controller can directly access main memory. The AGP channel is 32 bits wide and runs at 66 MHz (effective 133 MHz), double that of PCI's 33 MHz. AGP is in the middle, being superior to the PCI interface and inferior to the PCI Express interface.

AGP Versions

Available versions of AGP video cards are:

• AGP 1x

  32-bit channel at 66 MHz

• AGP 2x

  32-bit channel at 66 MHz double pumped

• AGP 4x

  32-bit channel at 66 MHz quad pumped

• AGP 8x

  32-bit channel at 66 MHz octuple pumped

• AGP Pro

  AGP Pro requires more power and are longer than standard AGP cards.

• 64 bit AGP

  Uses a 64 bit channel. Used in high end professional display adapters.

Two versions of the AGP interface exist. One for 3.3v and another for 1.5v video cards. These two versions are not compatible. Meaning 1.5v cards will not work in the 3.3v interface and vice versa. AGP Pro cards do not work with the standard AGP interface, but standard AGP cards will work in a Pro interface.

AGP Video Card Resources

• AGP Compatibility
• How AGP Works at How Stuff Works