Not sure where you are seeing 5MB up. It is 5 Mb down that is recommended, 3Mb is ok for SD content.
Now as for streaming, Video stream normally keeps sending data once the stream starts. Live TV breaks the stream down in to segments and new segment request happen every few seconds. Now if you have a slow turnaround time between the request and response the segment may not make it back in time. this would cause a freeze as the player now has to wait for the new segment.