Just running Conker in OpenGL, I am very happy with the speed. In OpenGL, we don't have to use software vertex clipper, and I have to use it in DirectX mode for my Radeon 9600. OpenGL seems to run more than double faster than DirectX in many places in the game. I can see the vi/s reading doubled with OpenGL, which means the video plugin is actually more than double faster.
With the fragment program extension (OpenGL Pixel shader), the graphics is as beatiful as DirectX with pixel shader.