   Bad Performance on Great GPU
  Hi!My DirectX application draws lots of particles. It needs a lot of fillrate and it's GPU bound on most systems. Antialiasing is disabled.On a HD3650 mobile graphics card, it runs very well.But some users have much better GPUs (GTX 260 or GTX 470) and report bad performance.Do you have any idea what could cause this? How can I investigate the problem when I don't have a test machine with a GTX260 available?Thanks!Lukas   
  - Try running the shader through nvidia's shader profiling tool.- It might be worth getting those people to try it with older / newer driver versions.- Can you get at any nvidia card to test it with?- Have you tried running it with the debug runtimes enabled on an nvidia card? They will pick up different issues on different hardware as the caps vary.- Check the actual frame rate on these 'slow' cards with say FRAPS.   