Hi All,

we designed a 3D medical project for CT and MR to draw a scene using
three different pixel shaders. It works on any video cards(Such as
nVidia, Matrox, ATI, etc.) on 32bit machine properly and under any
OSs. But it looks weird on nVidia Quadro FX 1300 on Dell Workstation
370( 64 bits machine).

The brief description about drawing is like:

- Clear 3D device
- BeginScene
- Select pixel shader A; Draw something
- Select pixel shader B; Draw something
- Select pixel shader C; Draw something
- EndScene
- Present

The weird performance looks like current scene is previous scene,
sometimes two scenes are mixed up.

What causes the problem? Does PCI Express card cause the problem? Does
new feature of new so-called generation nVidia card cause the problem?

When I draw three different parts of one texture on three different
viewports using three DrawPrimitive, it appears same part of the
texture on the screen. But when I draw the three different parts of
one texture on same viewport using only one DrawPrimitive, it works
properly.

yulong