This is a known problem, and it's known as coplanar faces. What's happening is your video card is trying to display two polygons in the same place at the same time, but since it can't it'll switch between the two objects.
The video card adjustments, and Directx settings change the way the video is buffered in memory (Z-buffer) so that helps to eliminate the problem in some cases.
@jimisham - I had that problem too in TRS2006 with some objects that had poor textures. I think it was the alpha channel for the texture. A single object would flash and make everything around it flash too. I ended up deleting those objects are replacing them with suitable replacements.
John