If we have a slow internet connection, we might have noticed YouTube videos getting stuck. The solution to this is to use SpeedBit Video Accelerator. This software will make your YouTube videos stream faster and play smoother by reducing buffering problems and video interruptions.
SpeedBit Video Accelerator is a product from the creators of Download Accelerator Plus (DAP).

Screenshot of the application.

How this work is that it makes more than one connection with the video file in the Youtube server so that it can download many video-file parts of the same video at the same time. The Speed Bit site gives us a pictorial representation.
Thanx : JohnTP