[Omega]

Are you talking about shutter speed, or image processing/storage speed, or what? I think that's going to vary from camera to camera, but with a 3 megapixel the processing time may be slightly greater, but then again they may just put a stronger processer in a 3 megapixel camera.

P.S. They'll generally list information such as shutter speed options and image processing time either on the manufacturer's site, or a thorough review site like Steve's Digital Cameras.