AGP evolution

[fizur2002]

i was looking at one of my old intel boards and i began to notice something, it appears that the agp slot is backwards in comparison to the newer cards, am i seeing things, or are the agp slots different from the older ones? tried using a rage turbo pro card on a shuttle board, but the notch was different. Maybe someone could help me figure this out.

[deadkenny]

There have been different AGP standards, with correspondingly different voltages. The position of the notch will prevent an incompatible card being inserted. Some dual mode cards have notches in 2 positions, to allow installation in diferent types of AGP slots.

[Peter M]

The slot isn't backwards. What you're seeing is the two positions for voltage support key tabs. The old board supports 3.3V signalling only (for 1x/2x modes) and hence has the no-1.5V key tab present; the new one supports 1.5V signalling only (4x/8x modes) and has the no-3.3V key tab present in the slot.

Cards are keyed the opposite way round; they have a notch in the respective position when they DO support a voltage. Universal cards have notches in both positions, universal boards have no key tabs at all.