We often get calls and emails about a customer’s internet being substantially slower than their subscribed plan while downloading content from Steam.
It’s highly likely that you are actually utilizing the entirety of your available bandwidth. The confusion comes with the different ways data is measured. Internet speeds are traditionally measured in Megabits per second or Mbps whereas downloads like Steam are often measured in Megabytes per second or MBps. There are 8 bits in a byte of data, so to find our your actual internet speed you would need to multiply the speed of the download by 8 to come up with the proper measurement.
Steam has heard this complaint many times, so much so that they wrote there own article HERE explaining the issue. Another useful resource to estimate your download time is to use a download time calculator like this one.