Hi MN, I too have the Mar '99 ATI and Open GL on a G3 with MacSys8.6 but disabled the ATI extension for the Rage 128 card since I don't have that particular card. With that extension 'on' I would get inconsistent but very frequent crashes during 3D renders. I wish that I could tell you more about how the system looks for the appropriate extensions but I can't :) I just know that with that particular extension off, everything has been smooth sailing ever since. The rest of the ATI and Open GL extensions are currently loaded on my system with no ill effects. I don't know if this helps but here it is! Mark