We have 25 megs on the downstream and 2 megs on the upstream. When doing a speed test without anyone downloading (from Usenet, for example), we get the full download and upload.
However, if one person is downloading at max speed (let's say, 3 megs per second), it brings down the internet for the rest of the house, even though we have 25 megs on the download and only 3 are being utilized.
Why is this? Why does throttling it slightly fix this problem?