Bryce (versions 3 and 4) can make use of OpenGL and Direct3D for accelerating its work window. In the period I used WindowsNT and a video card with good OpenGL support, the speed advantage on the OpenGL setting was quite something to behold. Now I'm back on Win9x and a Matrox card (poor OpenGL), nothing is significantly faster than Bryce's Sree3D software acceleration (also used by Poser). Except for the wireframe mode, of course, which is what I use. BTW, Bryce rendering is not accelerated at all by video hardware. Only a faster processor/memory system can speed that up.