The first thing that comes to mind is to update the graphics card drivers for your computer. I'm not sure if it will help but it's the first thought. If you can send a screen shot and also the 3dm file that would help too. The make/model and driver date of the GPU is also something I'd like to know. Can you send a screen shot of Options>Rhino Options>View>Open GL too?
Can you send the 3dm file to email@example.com referencing this thread or post it here? It might be GPU driver related or the PDF print driver you're using too. Check out the pdf995 driver listed on this thread... http://discourse.mcneel.com/t/display-questions/736/9 The user there also had the banding issue you mentioned with the gradient background.
Neon can only raytrace one viewport at a time. You can use ViewCaptureToFile though followed by PictureFrame to bring the rendered image back into Rhino and focus on that in a detail for the layout.
Send any other info and files if you can and I'm sorry things aren't just working for you here. There are a bunch of software drivers interacting and it's hard to know what's happening.