I will also add that the nVidia Quadro line of cards work much more smoothly with OpenGL than the GeForce line...so if you can switch like you say you can, it may or may not be worth a shot.
Again though, OpenGL is really only meant for 3D in After Effects, and it doesn't always do a great job on that.
Grant Swanson
Visual Effects Supervisor
Video Apex - Minneapolis, MN
videoapex.net