Dual Videocard under SuSE 9.3

Hi there List, I'm a bit puzzled and maybe someone can explain something to me.. I'm running SuSE 9.3 on two videocards. One is a NVidia AGP and the second is a Matrox Millenium II PCI. Sax is telling me that 3D on the NVidia is not possible, slowing down my desktop. My question is: Why? It is using two different drivers to run the two cards Right? Or am I missing something? Regards, Peter