Well baring any issues with your connection Steam does throttle its usage if there is a lot of load on the server you are connected to. Mostly at peak times. But 1mbps connection is pretty tiny these days, if you can upgrade you'll get much better performance. Scroll down to “Throttle Downloads” under “Preferences” Click on it and set your preferred download speed (in kilobytes per second) Now, hopefully, downloading an update or a game on the store.

Does Steam Throttle Downloads

Does Steam Throttle Download Speeds

Steam Throttle Download Speed

I have a very high quality business ISP that currently provides me 50gb per month. I run a web design company from home, and this has been plenty for me - never exceeded the limit, until my son started playing online games with Steam. Now he seems to use more bandwidth in a day than I do in a week.
Now I am looking into ways of sorting this out. Obvious one - 'You cant play online anymore' but he likes to play with his friends online. So I believe it is possible to do this with the QoS feature of my router - which is a Billion BiPac7800N.
It looks like I can assign different rates to different ports and IP addresses and protocol and direction. SO there should be some way of doing it. Anyone done this? Any tips for me?
Cheers
/j