Modo, my primary modeling tool, uses advanced OpenGL and it sings with my SLI card. I can turn off one of the cards (via the properties ... the 9800 GXT is really just two cards in one) and the hit my system takes in a 3D app is visible. I can also run DirectX apps with no problems. For example, I can run UT3 at the highest settings, full screen (my 24" monitor's resolution is 1920 x 1200) and the game is absolutely fluid.