To SWulfe: See if the VSync is turned off. That could be your problem because is what might be happening is that the Voodoo is displaying as many rendered frames as it can without worrying about the refresh rate of your monitor. In other words it tears or makes wierd screens. See if this is the problem, I think the driver settings are in the Display Properties, then Settings, then Advanced. Then you should see a tab in the 2nd row and it says Advanced Settings. Click it and you should see a list with "+"s and next to them it says Direct3D and OpenGL. Expand the OpenGL section and see if the VSync is turned off and if it is, set it to Software Controlled. Hope it helps.
To LePaul: Same for you, the overclocker should also be in Display Properties, then Settings, then Advanced. In the last row of tabs it should say 3dfx Overclocker. I must warn you though that it has caused problems in my system and in Aces High when i set it to anything above 166MHz.

BE CAREFUL!! Good luck to you. If I were you though, I would just leave it alone but if you have anything but Windows ME then go ahead and set it up at max 180 first. Then go little by little on testing.
I hope this helps you guys out.
Good luck and talk to you later.
