   How to improve DirectX performance?
  I was doing a real time display using DirectX .While measuring the performance i came to know that DirectX Present is taking more time about 260milli seconds for volume size of 29MB.I read in an article it is due to mode transition.Any one know a way to reduce that time please let me know.   
  What are you actually rendering? If it is just one massive vertex buffer (29MB like you said), performance is probably not going to be the same as a few DIP calls. Also, what kinds of state changes are you making? I believe some of these changes are cached and only made during the present call. This could be a reason why it is so slow.   