A serious problem has been found with GPU:3D and Windows 8, as it will crash upon startup. The root cause of this problem narrows down to the OS, as Microsoft seems to have completely broken the compatibility of DirectX10 with Windows 8.
I am planning two things regarding this issue : first, try to get a DirectX10 version running quickly, and then move on to DirectX11, as sticking with DirectX10 has no added value now that i have to use an updated SDK, and force dxwebsetup.exe to be run.
I'm currently working heavily on it, and hope to have a new beta out soon.
Meanwhile, you can use the DirectX9 test, which works under Windows 8.