I've set up a test machine with multiple PCI-e nVidia GF440 Video cards and installed Windows Multipoint Server 2011.
I use the same kind of hardware set up with a BeTwin multiseat solution to create a class lab for Google SketchUp teaching (highly OpenGL dependent) and it works ok.
On the Multipoint Windows test machine the drivers seem to be installed OK but I donĀ“t seem to get any hardware video acceleration. Is this a intrinsic limitation of this solution or am I doing something wrong?