I had a UGREEN Cat 6 cable running at 25m length across my house and I had issue using it on my laptop. Other than this, all other device such as router and desktop computer work fine without issue. As I only had a laptop, I couldn't try it on another laptop but I was suspecting the laptop wasn't transmitting enough power. Is the transmitting power of laptop ethernet really that low?

My laptop is using a Realtek ethernet and I'm using the latest driver also tried on older driver and hence I don't believe this is limited to only one driver version.

You need an AC type gigabit switch to extend your cat6 LAN cable connection to further distance. Last time I was bought a TP-Link TL-SG1016DE from Ookas (shopee) but they sent to me the wrong model TP-Link TL-SG116. Both gigabit switch are the same 16-ports but the different between them are TL-SG1016DE is AC type, TL-SG116 is DC type.

I was tested the TL-SG116. My network was unable to reach gigabit because the power output for TL-SG116 is quite limited. In the end they refund some amount back to me. I just put that TL-SG116 to my living room.

So I bought another new TP-Link gigabit switch TL-SG1016PE. This model is far more expensive because their first 8 ports are running in PoE. Finally, this gigabit switch was able to provide full gigabit speed to my whole house.

This post has been edited by junclj: Dec 14 2021, 05:44 PM

The cable is bad.

Some Ethernet NIC are more conservative and will not attempt to negotiate a link if the signal integrity is poor.

I would have to assume the latter as so far my desktop computer and my spare router doesn't have problem using the cable.