it's like the transition from the agp4x to agp8x only now the new standard is not compatible with the old one.
Old post above but just for posterity's sake...the statement above is incorrect. AGP compatibility is determined by the motherboard's AGP bus voltage and the graphics card's slot design...
Motherboard AGP Bus Voltage & Graphics Card Compatibility:
AGP 1x Bus = 3.3 Volts (compatible w/ 1x or 2x cards but not 4x or 8x)
*
AGP 2x Bus = 3.3 Volts (compatible w/ 1x or 2x cards but not 4x or 8x)
*
AGP 4x Bus = 1.5 Volts (compatible w/ 8x cards if the 8x card supports 1.5V)
**
AGP 8x Bus = 0.8 Volts (compatible w/ 4x or 8x cards but not 1x or 2x)
AGP Universal Bus (rare) = Voltage determined by card (compatible w/ 1x, 2x, & 4x AGP cards)
***
AGP 3.0 Universal Bus (rare) = Voltage determined by card (compatible w/ 1x, 2x, 4x, & 8x AGP cards)
***
*There are some universal cards that support 1x, 2x, & 4x buses (but not 8x). The card's slot design will look like this...{
Screenshot}
**The AGP 4x slot design is
physically identical to the AGP 8x slot design. As long as the AGP 8x card supports
both 1.5 & 0.8 voltage signaling, it will be compatible with an AGP 4x motherboard. Nearly every AGP 8x card produced before August 2006 supports both 4x & 8x buses.
***There are some rare motherboards with an
AGP Universal Bus or
AGP 3.0 Universal Bus. The regular AGP Universal supports 1x, 2x, and 4x cards, while the AGP 3.0 Universal supports 1x, 2x, 4x, and 8x cards. The correct voltage is automatically determined by the motherboard based on the card installed.
I'm not even going to start on AGP Pro compatibility because AGP Pro is virtually dead and irrelevant to most users anyways since it was most commonly found on servers & workstations.
