AGP - Advanced graphics port

AGPx1, 124 pin (voltage coded), 66MHz, 266MByte/s, 1x32bit word per clock cycle, 3.3V
AGPx2, 124 pin (voltage coded), 66MHz, 533MByte/s, 2x32bit word per clock cycle, 3.3V
AGPx4, 124 pin (voltage coded), 66MHz, 1066MByte/s, 4x32bit word per clock cycle, 1.5V
AGPx1/2/4 Universal
AGP Pro, 172 pin, 3.3V
AGP Pro, 172 pin, 1.5V
AGP Pro Universal
AGP Pro 50 v5.0 (50Watt max)
AGP Pro 110 (110W max)
AGPx8 (AGP 2.2, 'Beyond AGP')
AGPx8 (AGP 3.0, multiple AGP ports, reduced voltage 0.8V)

AGP 1.x spec (31.7.1996)
  AGP 1.0 (31.7.1996) AGP 2.0 +
ECR23 (17.2.1997)
AGP 3.0
signal name voltage current voltage current voltage current
Vddq I/O supply 3.0-3.6V max 5.0A 3.15-3.45V max 8.0A 1.425-1.575V max 2.0A
Vcc3.3 3.3V power 3.0-3.6V max 7.6A 3.15-3.45V max 6.0A 3.15-3.45V max 6.0A
Vcc3.3 AUX 3.3V power         3.15-3.45V max 0.375A
Vcc5 5.0V power 4.75-5.25V max 5.0A 4.75-5.25V max 2.0A 4.75-5.25V max 2.0A
Vcc12 12.0V power 11.6-12.6V max 0.5A 11.4-12.6V max 1.0A 11.4-12.6V max 1.0A
AGP 2.x spec (4.3.1998)
AGP 3.x spec (v1.0 [10. Sep 2002])
AGP Pro 1.0 spec
AGP Pro 1.1 spec

designed for fast transfers between system RAM and graphic card
obsolete if RAM on graphic card is big enough to hold all textures

  AGP 1.0 AGP 2.0 AGP 3.0
Signaling 3.3V 1.5V 0.8V
Protocol Pipelined transactions
+ Source synchronous clocking
+ Fast Writes
+ Some enhancements
– some deletions
Speeds x2, x1 x4, x2, x1 x8, x4
Connector 3.3V keyed 1.5V keyed / UNI 1.5V keyed

AGP slots
Mobo Edge PCI
AGP Pro 3.3V ->  AGP  <- 1.5V Retention
AGP all
  AGP 2.0 Pro
  AGP uni Pro
      AGP 1.0
      AGP uni
    1.5V Pro
    1.5V + 3.3V