Download accelerators split the file in to pieces and download each part parallely and finally join all these parts. If you use a broad band connection download speed can be increased by 10 to 200 times. This is not a exaggeration, you can find the screen shot of my download accelerator in action below. I usually get download speeds around 50 kbps speed without download accelerators, but it went up to 3.6 mbps with Mass Downloader.
Download Mass Downloader
Download Internet Download manager (IDM)
Download Download accelerator plus (DAP)
You can find a review of the above there download accelerators here
Yes..you’re right..it can be accelerated (i am a living proof) but not 10-200 times faster..let’s say 7-10 times faster..