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RT-AC86U Speed drops

Discussion in 'ASUS AC Routers & Adapters' started by Grega, Aug 23, 2019.

  1. Grega

    Grega Occasional Visitor

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    Hi,
    I have RT-AC86U running on Merlin 384.13_0. My Internet speed 1 gigabit from Comcast.I am getting the speed around 400 MB/s when the router works normally, but after a day or to my speed drops below 10 MB/s. Simply reboot puts the speed back to normal.

    Please let me know what setting I missed.

    [​IMG]

    Thanks,
    Gregor
     
  2. OzarkEdge

    OzarkEdge Very Senior Member

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    USA
    Have you tried other speed tests/servers?

    Tried connecting directly to the cable modem?

    OE
     
  3. Grega

    Grega Occasional Visitor

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    Yes. Using modem, I am getting 1 gigabit. This morning speed is again down to 20 Mbps.
    I attached log file.
     

    Attached Files:

  4. Grisu

    Grisu Part of the Furniture

    Joined:
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    2,296
    You cant have 400MB/s = Mbyte !!! on a gigabit line or any 1Gb LAN port, it should be 400Mb/s = Mbit.

    Is there any other wifi around, I had this symptom when 2 wifi routers where placed side by side even on different channels 1+5 and 9+13 then it went down <1Mb/s after some minutes.

    Is your problem only on wifi or LAN too?
     
  5. Grega

    Grega Occasional Visitor

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    only wifi
     
  6. Val D.

    Val D. Senior Member

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    What’s the client capable of?
     
  7. Grega

    Grega Occasional Visitor

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    MacBook Pro 13” model has a 2SS adapter in it and can reach a PHY rate of 866Mbps.
    Iphone 8 + not sure but definitely more than 10Mbps
     
  8. Val D.

    Val D. Senior Member

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    Is Smart Connect enabled on your router?
    If it is, then disable it and use separate SSID for 2.4GHz and 5GHz devices.

    Disable Auto channel (default Auto), select fixed channels for both 2.4GHz and 5GHz networks.
    Use 20MHz channel for 2.4GHz (default 20/40) and 80MHz channel for 5GHz (default 20/40/80).
     
    Last edited: Aug 25, 2019
  9. Grega

    Grega Occasional Visitor

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    Done. Thank you. Should I keep one SSID name for both channels?
     
  10. Val D.

    Val D. Senior Member

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    Must be different SSIDs. Connect all your 2.4GHz devices to 2.4GHz SSID and all your 5GHz devices to 5GHz SSID.
     
  11. OzarkEdge

    OzarkEdge Very Senior Member

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    Another tip... consider using something like Grega for the 5.0 GHz SSID and Grega-24 for the 2.4 GHz SSID. Then when you try Smart Connect and same SSIDs again later on, you can make them both Grega and not have to mess around with your 5.0 GHz client connections.

    OE
     
  12. Grega

    Grega Occasional Visitor

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    Thank you. All done. Now let's see if this will help.
     
  13. Grega

    Grega Occasional Visitor

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    This morning speed dropped to 20Mbps on both channels. After reboot, it went up to normal again (400-500).
     
  14. Val D.

    Val D. Senior Member

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    To check for potential compatibility issues with some of your clients try this:

    In Wireless -> Professional

    - TX Bursting Disabled
    - MU-MIMO Disabled
    - Beamforming (both) Disabled
    - Modulation 2.4GHz up to MCS 7 (n)
    - Modulation 5GHz up to MCS 9 (ac)

    In Wireless

    - Wireless Mode Auto
    - Protected Management Frames Disabled
     
  15. Grega

    Grega Occasional Visitor

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    Thank you. I will check settings later today when I come home from the office.
     
  16. Val D.

    Val D. Senior Member

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    Download something like Wifi Analizer on your phone and check what channels are least used in your place.
     
  17. OzarkEdge

    OzarkEdge Very Senior Member

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    Can you try a different router... yours may be ill. It sounds like a link in the chain is failing after a timeout from reboot... I would suspect hardware and start by swapping out the router.

    OE
     
    Last edited: Aug 26, 2019
  18. Grega

    Grega Occasional Visitor

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    All setting applied and channels set to a different numbers than neighbors have.
    Thank you,
    Gregor
     
  19. Grega

    Grega Occasional Visitor

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    My router is still under warranty until 2020/09/23. Which spare router should I buy if I need to return this one?
     
  20. OzarkEdge

    OzarkEdge Very Senior Member

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    Can you borrow one? I've got a box of old routers.

    OE