Another possible reason to use OpenGL is to enable 16bit mode for platforms that don't support it, or support it poorly. Mac OS only supports 15bit mode, and X11's 16bit mode is flaky (nobody uses it). Somebody has also speculated that a shader could be used to add up the bitplanes and display them, basically turning one's ATI or nVidia card into a planar video device. It's been years since I've messed around with OpenGL, so I don't know much about programmable shaders. I do know OGL 2.0 standardizes them to some degree. Anyway, I don't see these changes making as big a difference as a PPC JIT :)