OpenGL Accuracy on Radeon cards

Hi Everybody,
I have noticed that the ATI radeon [32MB DDR] has some problems with getting the lighting angle correct in OpenGL. I have used Indy3D for my benchmarking and in both MCAD tests the lighting is coming from a *low angle where as the reference image has the light source coming directly on the engine. Also, I noticed the the Z-buffer is only being read at 16 bit; and still objects close the the *camera are have z sort problems.
Has anyone else noticed any anomalous rendering *features of this card; I do not know if this warrants a return because the card is working even though I find it to be inaccurate.

My Radeon works great with no rendering errors. Have you tried updating the drivers? The latest 7020 drivers solves a lot of problem, get it at