video capture to 1280x1024 25 fps possible?

I have a webcam which capture video in resolution 1280x1024 to 15 fps, and in resolution 800x600 to 30 fps and my question is about if it is possible to capture video in 1280x1024 to 25 or 30 fps.

At this moment I make capture of video with VirtualDub and when I want to take to 1280x1024 and 25 or 30 fps does not leave me, since VirtualDub detects the limitations of webcam (I think). This is a general question to all the types of webcams that exist reason why it is not necessary to say the model of my webcam. Questions:

1) what thing prevents that this can be done? (controller, hardware...)
2) Is it possible to do an "overclock" to the webcam so that this mode 1280x1024 to 25 fps become possible?

Greetings!