Switches are dumb boxes that generally are not configurable. 50 MB/s transfer rate between wired machines is pretty common, 10 MB/s, something is going on. You said both 50 and 10, so I am not sure which you are seeing.
I would double check the lights on your switch and make sure they are sensing a gigabit connection.
I have a cheap Trendnet gigabit switch I bought on sale a few years ago and get 110 MB/s as a general rule between SATA III drives when transferring between 2 wired PCs. If one of your PCs is older and has a slow drive that too could be your issue.