colorfuldescent: Okay, so you are getting roughly one-eighth of your available speed when downloading from GOG. That's not good.
Do you share your Internet with others? Is it possible they are streaming/downloading in the background? Are you using a wireless connection, or a wired (ethernet) connection? If wireless, can you connect via ethernet and see if speeds improve?
What kind of hard drive do you have (for example, an HDD or SSD) and how much space do you have free on the drive?
I do not wish to sound rude however I was hoping for someone official to come onto this thread, unless you are in direct contact with GOG?
No I do not share with others, yes I have an ethernet cable, no my HDD is not SDD however the HDD you have makes no difference to my internet connection.