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Asus RT-ac86u ethernet ports slow....

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Max Nguyen

Occasional Visitor
So I have an rt-ac86u and thought everything was good.

Today I upgraded to fiber 300/300 from bonded adsl 100/up.

I would also hit my 100 on wired/wireless but as soon as I upgraded I can only hit 150 on ethernet and 300 on wireless. I tried mulitple cable and port, all the same result.

I ended plugging the ethernet directly into the router/modem from the internet provider and hit 300 when plugged in....

Anybody else notice Asus gigabit ports are slow??
 
Make sure it's not an MTU issues between the modem and router, and also make sure jumbo frames are supported/enabled on the 86U (most likely yes and already in effect automatically). Lastly, and most likely, make sure jumbo frames and MTU are set correctly on all wired interfaces on your client(s) that is/are exhibiting the slow transfers. That should fix your issue(s).
 
Make sure it's not an MTU issues between the modem and router, and also make sure jumbo frames are supported/enabled on the 86U (most likely yes and already in effect automatically). Lastly, and most likely, make sure jumbo frames and MTU are set correctly on all wired interfaces on your client(s) that is/are exhibiting the slow transfers. That should fix your issue(s).

Jumbo frames is not enabled my router or computer. It’s off by default on Merlin’s FW. Should I enable both then...on the router and computer? Where would I find MTU and what are the correct settings? Everything I read says don’t enable jumbo frame unless you are pulling data from a storage device etc


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Jumbo frames should have absolutely nothing to do with your WAN speeds. "Generally" jumbo frames are only for LAN to LAN high volume traffic flows.

Looking for confirmation here....

Via WiFi on the ASUS, you get 300Mbps.
Via wired on the ASUS, you get 150Mbps.
Via wired on the Modem, you get 300Mbps.

Is this correct? All tested with the same computer and cables?
 
I get WiFi speeds on 5GHz -wireless AC up to 575. Wired to my computer from router and modem or directly to the modem from computer I get between 175 to 250. Comcast can’t figure it out after 3 visits etc. I don’t know what else to do. Ethernet settings on computer and router both say connected at 1GB.


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Using a simple utility such as LAN Speed Test test the speed of transfers across you LAN using a wired client at both ends. If you have a NAS run it from the PC in question to the NAS. While this won't really test the router as the traffic will be handled by switch built into the router it will at least confirm if the LAN ports are correctly negotiating their settings.
 

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