TPLINK LAN speed defaults to 100/100 after PC is turned off

TPLINK LAN speed defaults to 100/100 after PC is turned off

TPLINK LAN speed defaults to 100/100 after PC is turned off
TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 11:49:39 - last edited 2025-07-08 09:13:38
Model: Archer AX1800  
Hardware Version: V1
Firmware Version: 1.1.1 Build 20240822 Rel. 42048(4555)

Hey,

 

 

I upgraded my home fiber to 500/500 from 100/100. I had to buy a new router and upgraded all the cables to support such speeds. After this I did get 500/500 and didnt think much of it, well the other day I was finally dowloading something and was confused why I was getting the same speeds as before and did speedtest and there it was 100/100. I did some digging in the settings and saw that my lan port was 100mbs full duplex. I changed these settings and finally got it to 1000mps full duplex. I shut my PC for the right and the next day we are back at 100/100. I have not found any info what could be resetting this and I have no idea how to even google something related to this. I wouldnt want to keep my PC on for no reason, but it irritates me that everytime I boot I have to do some magic in the settings and I dont even know what Im doing, just doing random things.

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#1
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1 Accepted Solution
Re:TPLINK LAN speed defaults to 100/100 after PC is turned off-Solution
2025-06-04 03:07:39 - last edited 2025-07-08 09:13:38

Hi@YeehawWeewoo,

Thank you for contacting our community.

 

As terziyski said, it is recommended that you can try different cables for a comparison. 

When the speed drops, please connect the PC directly to ISP modem. Which is to confirm if the speed of modem drops at the same time.

In addition, please try to hard reset the router and configure it again. 

How to reset: Press and hold reset button for 2 seconds until all LEDs turn off to reset the router to its factory default settings.

 

Best Regards~

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#9
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 18:53:19

  @YeehawWeewoo 

 

Check your ethernet port status here:

 

 

If the negotiated speed on port where you've connected your PC is 100 mbps, move the PC to a different port and if that doesn't help change the ethernet cable. 

If this was helpful click on the arrow pointing upward to make it blue. If this solves your issue, click the star to make it blue and mark the post as a "Recommended Solution".
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#2
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 18:56:15
Problem is like I said, it defaults back to 100. I have set the negotiation to 1000 and I can get 1000/1000 out of it. I shut my pc off and go check the port and its back to 100/100 even when ive set the negotiation to 1000/1000.
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#3
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 18:56:58
I just cant see how my cable would be the cause, its capable of handling 1000mpbs but still defaults to 100 after reboot.
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#4
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 19:03:39

  @YeehawWeewoo 

 

So you have this issue with the WAN port, but your PC is connected to a router LAN port, correct ?

If the problem is with the WAN port then you can only test with another cable.Normally WAN port should be set to Auto negotiate its bandwidth.

Sometimes if ethernet cables are not of a good quality, behave like this (most often) and sometimes router WAN port is faulty (less often).

If this was helpful click on the arrow pointing upward to make it blue. If this solves your issue, click the star to make it blue and mark the post as a "Recommended Solution".
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#5
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 19:50:13
WAN port has always been 1000/1000, that has not changed at all at any point. LAN port is the one changing after boot, Ive also testedifferent lan ports, issue persists.
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#6
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 20:13:13 - last edited 2025-06-02 20:51:31

  @YeehawWeewoo 

 

" I have set the negotiation to 1000 and I can get 1000/1000 out of it. " This setting is only for the WAN (Internet) port:

 

If the LAN port speed is 100mbps instead of 1000mbps, try changing the ethernet cable as I suggested earlier.

Updating PC network card driver to the latest release might help as well.

If that still doesn't help you can contact your local support for further assistance.

If this was helpful click on the arrow pointing upward to make it blue. If this solves your issue, click the star to make it blue and mark the post as a "Recommended Solution".
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#7
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off
2025-06-02 20:25:06
Well when I change negotiation it doesnt change the value on WAN but does change it on the LAN, so I have hard time understanding how it would not affect LAN?
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#8
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Re:TPLINK LAN speed defaults to 100/100 after PC is turned off-Solution
2025-06-04 03:07:39 - last edited 2025-07-08 09:13:38

Hi@YeehawWeewoo,

Thank you for contacting our community.

 

As terziyski said, it is recommended that you can try different cables for a comparison. 

When the speed drops, please connect the PC directly to ISP modem. Which is to confirm if the speed of modem drops at the same time.

In addition, please try to hard reset the router and configure it again. 

How to reset: Press and hold reset button for 2 seconds until all LEDs turn off to reset the router to its factory default settings.

 

Best Regards~

Recommended Solution
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#9
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