Synopsis: Experiencing extremely low network speed with laptop connected to the monitor's USB Type-C and a GigE USB-3 dongle attached to one of the USB-3.0 ports of the monitor. Internet speed = ~30 Mbps! Direct attachment of GigE dongle to laptop yields ~350 Mbps.
Laptop: experimented with Lenovo X1 Carbon 6th generation and Microsoft Surface Book 2.
OS: Windows 10 Pro for both experiments.
Laptop connected exclusively through the USB Type-C cable to the U3818DW monitor. No other cables are attached to the laptop.
Plugable USB-3.0 GigE adapter connected to one of the USB-3.0 ports on the bottom of monitor. Experimented with both bottom ports and got the same result.
Experimented with a different brand of GigE adapter: Cable Matters USB-3.0 GigE Adapter. Identical results.
In all experiments described above, the Ethernet adapter status in Windows-10 reports the adapter operating at 1GBps. There are no driver issues with either of these common adapters.
Folks, has anybody seen a similar phenomenon? I wonder if my monitor's built-in USB hub is broken.
I understand that the USB rate will drop to the USB-2.0 speed once the laptop communicates with the monitor at full resolution. However, USB-2.0 speed is rated at 480 Mbps. It should have not created a bottleneck for my Internet speed which cannot exceed 350 Mbps. At least not this dramatic throttle - 30 Mbps.