Well, as I can see there's nothing wrong with your model. It's clean and neat. I also have ati but this image is from PC that has some intel onboard card. Display is ok on both of them so only thing that I can think of is that you try to update your drivers.

P.S. Only thing that pokes my eyes in your model is that loose vert and edge that goes from top of that dome down to it's base :)