Hello! I have a strange texture problem with my D3D8 terrain renderer... I have 1024 vertex buffers with 16x16x2 triangles each, so my map have the dimension 512x512 squares. But only 4 vertex buffers are visible each frame, so I only render 2048 triangles (16x16x2x4) each frame and call SetStreamSource 4 times each frame. All vertex buffers have the same texture and I call SetTexture only ones before the app start. What I don´t understand is when I don´t call SetTexture I get 240 fps, and when I call SetTexture I get 40 fps Why?? Like I said, I call SetTexture only ones and SetStreamSource only 4 times each frame! When I decrease the size of my map to 64x64 squares I get good performance (200+ fps) whether the texture is set or not.

Textures in system memory?
that''s very wrong!