Douglas,
40 Megabits/s in digital storage is divided by 8 or 5 MebiBytes/s. You will likely not hit that perfect limit due to some network communication overhead and packet loss across distant links.
Your connection transfer speed will be limited to the slowest bottleneck link.
If you were on the same LAN connected directly to the same switch, the speed would be limited to the link speed of the switch minus network overhead.
If transferring over the internet, the speed would be limited not only to the slowest peer, but also the relay servers being used on the internet. For example, even if I have a 1Gbps connection, I'm not going to get those speeds if transferring with someone who only has a 1Mb/s connection. Additionally, even if both sides had a 1Gbps connection, if a router or network device in between (such as a relay server used to bypass firewalls or a slow switch) has a slow link, transfers will be limited to the slower speed.
Based on your reported problem, I would assume you are using Remote Utilities' public relay servers in which case data speeds may be limited / shared with other users. To bypass this, you need to allow direct communication or set up a publicly accessible relay server. This may involve opening firewall ports or forwarding traffic through routers. See the following support pages for more information.
https://www.remoteutilities.com/support/kb/what-is-a-direct-connection/https://www.remoteutilities.com/support/docs/ports-used-by-remote-utilities/
