OpenGL works fine on my card, fixes some of the stuttering issues I've had, though usually I've used D3D for stability issues. Under the latest build I've used I get those white squares too, but what's funny is... The white squares will change to other textures! Each "tile" will change from pure white to an explosion animation, then to a planet that's used in the background. This usually happens when I'm playing the FS Conversion and it really only happens to the Orion destroyer. I'll get random white squares.
I've not tested under OGL. Great to see the shineys back!!