   PIX and large textures
  I have a volume texture 512x1024x128.  My Geforce 8800 GTS has MaxVolumeExtent = 2048 according to Caps Viewer.  The volume renders fine, but when I try to debug using pix, I get an error in PIX "Error in call data" at the point it tries to draw the volume, and I have discovered that the problem line is the one that sets the volume texture to the effect.  If I switch to a 512x512x128 volume, then PIX works fine.  Would PIX have an issue with larger volume texture for some reason?   
  Which SDK are you using? A lot of the work which goes into the SDK updates is for PIX. If you're not using the August 2008 SDK, I'd suggest updating to that and trying again.   