Whole wired network running at Gigabit speed, but one Mac can't get full-speed fibre internet?

[AVR2]

My wired home network is comprised of two Macs downstairs and one upstairs, all connected by Cat6 cable into my fibre router, which has an integrated 4-port Gigabit switch. The Macs are all Gigabit-capable, and I've used a local network speed test tool to confirm that they are talking to each other at Gigabit speeds; the peak speed between the two furthest-apart Macs on the network is 925 Mbps, the average is 890.

My fibre broadband speed is 650 Mbps and the Ookla speed test confirms that both the Macs downstairs are getting pretty much that. But for some reason, Ookla is showing that the upstairs Mac maxes out at about 350 Mbps. Why might that be? There's nothing stealing bandwith from it when I run the test.

I've confirmed that all the Macs on the network are communicating with each other, via the switch in the fibre router, at an average speed of 890 Mbps, so on the face of it, it doesn't look like a cable issue.

 

[satcomer]

Learn the difference between megabytes and megabits and understand each compony tries to trick you in speed!

 

[AVR2]

Learn the difference between megabytes and megabits and understand each compony tries to trick you in speed!

Sorry, that is not a remotely helpful reply.

Why are the two Macs downstairs reporting 650 Mbps internet speed and the Mac upstairs only 350 Mbps, given that the upstairs one is communicating with the fibre router at the same local network speed as the two downstairs ones?

 

[glenthompson]

Can you move one of the downstairs Macs to the upstairs location and test it? That would tell us if the problem follows the machine or the location. Does the upstairs Mac have WiFi turned on? If so what is the primary interface in network settings? Which model Macs are we talking about here?

 

[StephanieSy]

Fiber Cables or Copper Cables?

 

[satcomer]

Sorry, that is not a remotely helpful reply.

Why are the two Macs downstairs reporting 650 Mbps internet speed and the Mac upstairs only 350 Mbps, given that the upstairs one is communicating with the fibre router at the same local network as the two downstairs ones?

Yes it is one company measure into bytes (Windows) and other to megabytes (Apple, Linux)! besides W-Fi diminishes the father away from wireless router! Beside what ethernet is between the router and the upstairs cat5, 5E, 6A or better going up?