[SOLVED] Issues with internet speed capped at 100Mbps and possible solution

[DroP90]

I have 300MB connection and didn't noticed any limitation until today after I formatted my PC and reinstalled Windows 10, the speed was capped at 100MB afterwards (downloading at 11MB/s maximum). I thought it could be something related to drivers so I formatted again and manually installed the LAN Driver, problem persisted. Tried variety of things and nothing worked, the problem was with my PC or the cable since the connection over wi-fi was okay.

After some more troubleshooting I found this solution that worked, going to Ethernet Status at Control Painel, my Speed was set to 100Mbps, in the Advanced tab I changed the Speed & Duplex from Auto Negotiation to 1.0Gbps/Full Duplex, after this I reconnected the cable and my speed is fixed, downloaded a big file with the same constant speed that I had before (~35MB/s).

The thing is, I searched more about it and found this article from Intel stating that " We have had reports of some ISP technicians telling their customers that a Gigabit option will appear in this setting if the network adapter is working correctly. This is incorrect. Auto Negotiation is the correct setting for Gigabit speeds in Speed & Duplex for Killer Networking Adapters. There is no option for 1.0 Gbps Full Duplex with our Ethernet drivers. Auto Negotiation will give you a 1.0 Gbps link speed, provided your other networking equipment auto-negotiates correctly. "

Now I don't know what to think, it's clear that changing the option fixed my issue, but I'm afraid now that the cable isn't really okay and I should change it. My biggest fear is: changing this Speed & Duplex option could damage the LAN port from my Motherboard or the Modem?

 

[Lutfij]

Which version of Windows 10 are you working with? You can find that bit of info by Right click Start>System>to the bottom of the new window.

As for your motherboard, what is the make and model of the unit? What BIOS version are you on for said motherboard? As for the drivers, manually install drivers from your motherboard(if it's the NIC bundled with the board) manufacturer's support site in an elevated command, i.e, Right click installer>Run as Administrator.

 

[Ralston18]

No - that change will not damage the LAN port.

 

[bill001g]

It won't hurt to leave it configured that way but setting it to auto is a better option. Sometimes the port on the router will get confused when it is running auto and you have yours set to some fixed value. It might actually drop to 10mbps half duplex and the port will go down. To set it to a fixed value you really are suppose to set both ends and most routers do not have the ability.

The only option for gigabit is full duplex which is why many drivers do not allow you to set it. I have seen systems you can actually set gigabit half duplex but that is not really a valid things to do so I don't know what happens if you would do it.

 

[DroP90]

Which version of Windows 10 are you working with? You can find that bit of info by Right click Start>System>to the bottom of the new window.

As for your motherboard, what is the make and model of the unit? What BIOS version are you on for said motherboard? As for the drivers, manually install drivers from your motherboard(if it's the NIC bundled with the board) manufacturer's support site in an elevated command, i.e, Right click installer>Run as Administrator.

Windows 10 version 21H1
My MB is an Asus B460M-Plus

So like I said, everything was okay until I formatted, 1st time I let the Asus Software (Armory Crate I guess) install drivers, then stumbled on this problem and tried to roll back the LAN driver, installing it manually from my motherboard official page, no success, so I decided to format again and manually instal the drivers, still no success until I found this solution going into the Ethernet options and changing the Speed & Duplex from auto to 1.0Gbps.

Another thing that I noticed, before the solution, my internet wouldn't connect at system start, taking some 30 to 40s, now it's connecting as soon as I get on the logon screen, like it was before formatting.

It won't hurt to leave it configured that way but setting it to auto is a better option. Sometimes the port on the router will get confused when it is running auto and you have yours set to some fixed value. It might actually drop to 10mbps half duplex and the port will go down. To set it to a fixed value you really are suppose to set both ends and most routers do not have the ability.

The only option for gigabit is full duplex which is why many drivers do not allow you to set it. I have seen systems you can actually set gigabit half duplex but that is not really a valid things to do so I don't know what happens if you would do it.

Auto was capping my speed to 100Mbps, I can't realize why since before the format everything was okay and I've never experienced this problem before.

But I agree with you, I shouldn't need to go to a advanced option to make my full internet speed viable, something is off and I don't know for sure if it's my ethernet cable or Windows 10/Drivers...

 

[DroP90]

UPDATE! FIXED!

I decided to put at Auto to see what happens and for my happy surprise the speed stayed at 1.0Gbps, letting my internet to reach the full 300MB that I pay for.

 

[bill001g]

If it drops back again later you likely have a bad ethernet cable. In some ways it would be nice if bad ethernet cables just stopped working but one that is marginal can randomly change speeds.