^^ In that qupted post, he meant AGP....
AGP
PCI
PCI express
Those are all 3 PHYSICALLY different interfaces on motherboards. TYPICALLY, AGP is brown, PCI & PCI Express are white...
If you do a google image search, you should be able to find what the different interfaces look like. NONE OF THEM AR COMPATABLE WITH EACHOTHER! AN AGP card WILL NOT work in a PCI or PCI Express slot.... PCI card won't work in an AGP or PCI express slot., etc. etc. etc.