[question]access frame data from video card memory directly

Hi everybody,
I am using NVIDIA GPUs to develop a application. This application retrieve the screenshot with DirectX. But the interface is very slow. I use GetFrontBufferData(). Microsoft said “This method is the only way to capture an antialiased screen shot. This function is very slow, by design, and should not be used in any performance-critical path.” So I am finding another way.
In fact, when I get the frame, I will use CUDA to do some computation on it.
I intend to use assembly or some other resources which are used to write GPU driver. I think if I use the most basic interface provided by NVIDIA, maybe I can have the authority to access the frame buffer on GPU. I do not find any useful information for this idea, yet. Could you give me some advices.
Many thanks for your reading. I am waiting for your reply. Thanks in advance.

My Best Regards,

Hi, have you found the answer for your question?