I installed Zorin 7 earlier today, and have discovered that when installing games in steam, the download speed starts out normal, but almost immediately drops to less than half the download speed that I was getting in windows. I'm on a wired connection and when I test my connection in sites like speedtest, It comes up normal.
I'm completely stumped, and can't find a solution, any help would be appreciated. Note that I'm a wet behind the ears Linux noob, so some handholding may be required.
Try using a different source, other than Valve's servers, to test your download speed. Considering it's the Summer Sale, their servers are getting maxed out right now which will affect your download speed.
As for apparent slower speeds on Linux, it may be because it was using different Valve servers when on Linux and on Windows. Make sure the settings on your Steam client in Linux are set right e.g. don't have speed capped, and your download region is appropriate
Let me clarify what I'm actually experiencing, my download speed will start out at 5mbs, which is what I normally get in windows, it then gradually drops to around 2.5 mbs in about 30 seconds. After a few minutes, it drops down to about 1.5mbs.
Due to the summer sale, Steams servers are getting destroyed by everyone downloading games at the same time. I can barely get on to look at the sales for the first hour after each daily sale.