F5F Stay Refreshed Power Users Networks Why does my Ethernet connection stop when I use full-duplex mode?

Why does my Ethernet connection stop when I use full-duplex mode?

Why does my Ethernet connection stop when I use full-duplex mode?

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mazZterSPro
Member
52
04-30-2026, 03:24 PM
#1
I just finished setting up my new PC a few days ago. All drivers are installed and updated too as well as my BIOS settings. But when I use my ethernet connection at 1Gbps, Windows thinks I am plugging in and unplugging my LAN cable constantly. It connects and disconnects around 10 times every minute or more. If I force my speed and duplex setting to 100mbs half duplex it starts working normally. I've used the same cable with another PC and it worked fine at 1Gbps without any problem. Modem supports those speeds and my ISP is giving out 1000mbs up and download for sure since I've tried with my laptop and another desktop. Bought a new cable today to double check and same with both my CAT6 cables. I have an ASUS Rog Strix Z790-A motherboard and the Intel Ethernet Controller I226-V. I've thought of it being a driver issue but I can't find any older drivers for this ethernet controller. The one I have is driver version 1.1.3.28. So basically does anyone know what the problem might be and how to fix it?
M
mazZterSPro
04-30-2026, 03:24 PM #1

I just finished setting up my new PC a few days ago. All drivers are installed and updated too as well as my BIOS settings. But when I use my ethernet connection at 1Gbps, Windows thinks I am plugging in and unplugging my LAN cable constantly. It connects and disconnects around 10 times every minute or more. If I force my speed and duplex setting to 100mbs half duplex it starts working normally. I've used the same cable with another PC and it worked fine at 1Gbps without any problem. Modem supports those speeds and my ISP is giving out 1000mbs up and download for sure since I've tried with my laptop and another desktop. Bought a new cable today to double check and same with both my CAT6 cables. I have an ASUS Rog Strix Z790-A motherboard and the Intel Ethernet Controller I226-V. I've thought of it being a driver issue but I can't find any older drivers for this ethernet controller. The one I have is driver version 1.1.3.28. So basically does anyone know what the problem might be and how to fix it?

D
DzoniGamer_YT
Member
52
05-02-2026, 11:34 AM
#2
You probably need to seriously worry about having bad ethernet cables. Speed negotiation happens at a hardware level and doesn't really rely on software drivers. So, if you have bad cables, a broken port in your router, or a faulty port on the computer, you'll likely be in trouble. Honestly, just because an Ethernet cable works in other people's machines doesn't mean it will work for you. Some marginal cables might function fine with one device but fail with another. Also, ports that are 2.5 gigahertz (2.5g) are very sensitive to bad or incorrect cables. A huge issue right now is the flood of fake ethernet cables on Amazon. Most of them look like flat cables where the wire is too small to meet the official certification standards for an Ethernet cable. All you really need are Cat 5e pure copper cables with a wire size between 22 AWG and 24 AWG.
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DzoniGamer_YT
05-02-2026, 11:34 AM #2

You probably need to seriously worry about having bad ethernet cables. Speed negotiation happens at a hardware level and doesn't really rely on software drivers. So, if you have bad cables, a broken port in your router, or a faulty port on the computer, you'll likely be in trouble. Honestly, just because an Ethernet cable works in other people's machines doesn't mean it will work for you. Some marginal cables might function fine with one device but fail with another. Also, ports that are 2.5 gigahertz (2.5g) are very sensitive to bad or incorrect cables. A huge issue right now is the flood of fake ethernet cables on Amazon. Most of them look like flat cables where the wire is too small to meet the official certification standards for an Ethernet cable. All you really need are Cat 5e pure copper cables with a wire size between 22 AWG and 24 AWG.

M
Mr_Gloku
Member
211
05-18-2026, 03:48 AM
#3
Alright, I will get a brand new ethernet cable tomorrow to check if everything works.
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Mr_Gloku
05-18-2026, 03:48 AM #3

Alright, I will get a brand new ethernet cable tomorrow to check if everything works.

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TobiasJelskov
Junior Member
16
05-18-2026, 11:10 AM
#4
Maybe your internet connection is shaky. Try swapping out the cable for a new one. If that doesn't work, you can try sticking some electrical tape around the RJ45 plug to give it more room. I have a laptop that has this exact problem with my ethernet port. I did okay because I used the same trick: wrapping an electrical tape around the connector of the cable.
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TobiasJelskov
05-18-2026, 11:10 AM #4

Maybe your internet connection is shaky. Try swapping out the cable for a new one. If that doesn't work, you can try sticking some electrical tape around the RJ45 plug to give it more room. I have a laptop that has this exact problem with my ethernet port. I did okay because I used the same trick: wrapping an electrical tape around the connector of the cable.