thanks for clarification ,

I need to ask one last question since I am new to shader programming ,

I am not crystal clear sure how mechanics behind the scenes are so ,

As it has been said , it is Shader Model 3 with DX9 which is the latest SM I can use, what about using DX9 and NvidiaCG together instead of HLSL ?

So it wouldnt change anything would it ?

Actually I am after to learn how the graphics API itself is a bottleneck for the latest shader model we can use , if the shaders are being compiled externally and targeted for GPU

Haven't explicitly checked myself, but I really doubt it (these profiles are from an old version of Cg, couldn't find a newer table). You still have to (want to?) load your shader in a DX 9 context, so you're limited to SM 3. By the way: Cg can compile HLSL code.

To get more features from your card you have to use a different API (DX10, OpenGL, or even OpenCL, CUDA).

glSmurf and unbird , thanks a lot , you ve been very helpful