Every time I load a video lets say a minute long it would load the first bit of the video really quickly and the rest real slow. i've updated java and flash player and still get this problem. The internet connection is not the case because I have ADSL2+ and get over 15mps, but when ever i download a file from a website the speed is very steady, is it to the modem I don't know

I have tried it with my other computer and it does also with that one. When i click to watch a video the lights on the modem flash fast and 1-3 seconds later it becomes really slow for like ADSL 2+ so it must be the modem, but regular downloads are very steady as mentioned before