This is a capture I made from my application:

http://www.teleportmedia.com/roleworld/line_bug.htm

The application is well optimized, it runs at 2% of CPU usage. I'm using DirectX 9.

You will see horizontal lines jumping from time to time. Something I don't see with for example a character's mesh, only with this blocky level. Those lines are not related to gaps between the vertices, and there aren't overlaping faces.

I set the anysotropic filter to the maximum according to the device capacity. The texture is quite big (2048x204 but my NVidia should support it. I tested with resampled versions of the same texture, .dds files of 1024x1024, 512x512 and 256x256, and also with mipmaps, and the bug persists. I tried different angles of the camera (pitch and yaw), and diferent elevations... the bug remains.

Then, I have no clue what could I do. Could any one help me? :?