I'm trying to download Terraria in this case, and I have tested the download speed of this computer's adapter already; 1.5mb/s. Despite this, downloading things in Steam will only reach up to 150kb/s. I have switched from 4 servers, I live in Florida so I tried Houston, Atlanta, New York, and Miami. All 4 gave me the same speed or worse. Please help.
I have another computer with Steam on it that runs Windows 10, but can download up to 3mb/s. This is an issue on here.
EDIT: I do recommend checking all the solutions people have given, it doesn't seem my solution was universal. Hope you can figure it out here.