direct3d 9: mouse interference causes drawprimitive loss of triangles

I have a direct3d 9 application which renders correctly with ATI rage,
but not with ATI radeon 7200 or Nvidia geforce mx 2, with latest drivers.
I have lots of trouble: flat shaded instead of gouraud, bad clipping,
bad lighting, there is interference when mouse is moved across the window
which is either due to shared interrupts with video board or other problem
with system wide locks interfering with the hardware rendering, I can send
you the program so you check.



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Dott. Ing. Guglielmo Fanini