Download speeds

Hi. Maybe someone can shed light on this. With my internet provider my download speed (tested) is between 5 and 5.5Mb/sec
but when I download from sites using Luckyshare, Rapidshare or Rapidgator the fastest download speed I get is apx 600Kb/sec. Is this the same for all?

Thanks.

You can test your ISP speed here - http://www.speedtest.net/

My ISP speed is 5Mb/sec. The download speed when I download from Lukyshare , Rapdgator etch is never more than 500 to 600 Kb/sec