Latitude 5290 2-in-1, DA300 ethernet fails to run at 1Gbps

Question

I'm using a Latitude 5290 2-in-1 tablet with i7 8650u inside. All of my peripherals and router is running at 1Gbps while the ethernet connection of DA300 dock can only run at 100Mbps half duplex and sometimes drop to 10Mbps even if I manually set the connection speed to 1Gbps full duplex. All of my cables are Cat 6.

Egdireubl · Answer

I'm having the same problem with DA300 connecting to XPS 7390 2-in1. The Ethernet port on DA300 is running only 100Mbps link speed. Tried updating the Realtek driver a couple times and now up to version 10.45.20.308 [3/7/2021] doesn't help. With everything the same, when plug in the Belkin USB-C Docking Station (which has the same Realtek 8153 Rev_300 chip onboard), the link speed is at 1 GbE instantly. What can be wrong? Does any one have any success with DA300 running at GbE?