Question ASUS RT-AC86U Capping Download Speeds (Ethernet Only), help fixing please.

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
Hi so basically I have had the RT-AC86U for a while now and its been pretty good helped me out a lot.

Although its now started to cap my download speeds with ethernet not through the WIFI signal of the router.

Basically I pay for 1000mbps and I get around 950mbps when all is working fine on ethernet but recently it has been doing an issue where it just caps itself at 80/90mbps through the ethernet. It used to do this but I found it was when it needed a router firmware upgrade it would do it so upgrading the firmware fixed it. But now a days it just does it without a firmware upgrade being available.

I can fix this however by restarting the router but this happens so often that its not viable to keep doing it.

I have turned QoS off as this caused similar issues in the beginning and also turned the firewall off but I have no idea why it keeps doing it or how to fix it permanently.

This only happens for download speeds also the upload speed always stays the same as I get whenever.



TLDR:
Router caps download speed randomly, can fix with a restart of router but not viable and want a more permanent fix if possible.

Thank you anyone that can help!
 

kanewolf

Titan
Moderator
Hi so basically I have had the RT-AC86U for a while now and its been pretty good helped me out a lot.

Although its now started to cap my download speeds with ethernet not through the WIFI signal of the router.

Basically I pay for 1000mbps and I get around 950mbps when all is working fine on ethernet but recently it has been doing an issue where it just caps itself at 80/90mbps through the ethernet. It used to do this but I found it was when it needed a router firmware upgrade it would do it so upgrading the firmware fixed it. But now a days it just does it without a firmware upgrade being available.

I can fix this however by restarting the router but this happens so often that its not viable to keep doing it.

I have turned QoS off as this caused similar issues in the beginning and also turned the firewall off but I have no idea why it keeps doing it or how to fix it permanently.

This only happens for download speeds also the upload speed always stays the same as I get whenever.



TLDR:
Router caps download speed randomly, can fix with a restart of router but not viable and want a more permanent fix if possible.

Thank you anyone that can help!
Start by doing a factory reset on the router. There are many options which can limit speed because they require the CPU to process all traffic.
After the reset do a minimal configuration -- Just admin password, SSID and WIFI password. Then retest.
Your "80-90mbps" sounds like a bad cable. You need to test with a new cable. Nothing fancy, just a cat5e 100% copper cable. Not flat, or "cat 8" or anything fancy. If you have any in-wall cabling, that is the first place to look. One of the wall plates can be bad. You can replace the jumper cables, but not fix the problem.
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
Start by doing a factory reset on the router. There are many options which can limit speed because they require the CPU to process all traffic.
After the reset do a minimal configuration -- Just admin password, SSID and WIFI password. Then retest.
Your "80-90mbps" sounds like a bad cable. You need to test with a new cable. Nothing fancy, just a cat5e 100% copper cable. Not flat, or "cat 8" or anything fancy. If you have any in-wall cabling, that is the first place to look. One of the wall plates can be bad. You can replace the jumper cables, but not fix the problem.
Hi thank you for the response, the cable is fine I think because I tried another not fancy cable when the issue happens on my main pc directly in and it still does the same issue which makes me think its a router issue?

Its just direct also nothing in walls.
 

kanewolf

Titan
Moderator
Hi thank you for the response, the cable is fine I think because I tried another not fancy cable when the issue happens on my main pc directly in and it still does the same issue which makes me think its a router issue?

Its just direct also nothing in walls.
Did you do the factory reset on the router ?
Have you verified that you do have gigabit speed on your network adapter? You should also be able to see the link speed in the GUI to the router.
Check the WAN link speed on the router.
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
Did you do the factory reset on the router ?
Have you verified that you do have gigabit speed on your network adapter? You should also be able to see the link speed in the GUI to the router.
Check the WAN link speed on the router.
Hi mate,

I have been unable to do it currently as my house mate is working from home I am going to do it a little later on when hes done.

Yes it definitely has the speed I have just checked the WAN speed this is it, I presume its the top one and I use a gigabit network switch to give it to my others.

https://prnt.sc/W1NoeGJE8pmY
 

kanewolf

Titan
Moderator
Hi mate,

I have been unable to do it currently as my house mate is working from home I am going to do it a little later on when hes done.

Yes it definitely has the speed I have just checked the WAN speed this is it, I presume its the top one and I use a gigabit network switch to give it to my others.

https://prnt.sc/W1NoeGJE8pmY
That is showing the two LAN ports only linked at 100Mbit. THAT is your problem. Ethernet cable is the usual reason for that.
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
That is showing the two LAN ports only linked at 100Mbit. THAT is your problem. Ethernet cable is the usual reason for that.
Ok would it be like switching? As in cos it works fine sometimes but then others it doesnt if it goes to full speed when I check will it say 1gb?

Also I will buy another cable just a round cat5 one should be fine?
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
IMO, yes. If it doesn't reliably negotiate gigabit, and there is nothing but two devices with an uninterrupted cable between them, then the cable is the most likely problem.
Oh I do have a network switch in between them actually I will try run some tests next time it faults out. And see if I can get my 1gb when directly plugged in and again if I put the network switch in between.

Thanks
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
IMO, yes. If it doesn't reliably negotiate gigabit, and there is nothing but two devices with an uninterrupted cable between them, then the cable is the most likely problem.
Hi Kane,

Just checked, so it was 100mbps then I restarted the router it went to 1gbps.

Then after that I restored the router to factory and its back to 100mpbs this is all with a new cable, which makes me believe it could be the settings. Could you advise me some settings I should change now to try get it back to working full order.

Thank you
 

kanewolf

Titan
Moderator
Hi Kane,

Just checked, so it was 100mbps then I restarted the router it went to 1gbps.

Then after that I restored the router to factory and its back to 100mpbs this is all with a new cable, which makes me believe it could be the settings. Could you advise me some settings I should change now to try get it back to working full order.

Thank you
There are no settings. Autonegotiate is done in hardware.
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
There are no settings. Autonegotiate is done in hardware.
Ok I think best option I have is just wait for it to do it again and when it does swap some cables out.

I realised I was using from my router in modem mode to my router a Cat 7 Flat cable which could have not helped either.

So I am going to wait it out for now and try and swap a few cables out when its going slow just to plain Cat 5 e.t.c and skip my network switch and see if it works.

Many thanks
 

kanewolf

Titan
Moderator
Ok I think best option I have is just wait for it to do it again and when it does swap some cables out.

I realised I was using from my router in modem mode to my router a Cat 7 Flat cable which could have not helped either.

So I am going to wait it out for now and try and swap a few cables out when its going slow just to plain Cat 5 e.t.c and skip my network switch and see if it works.

Many thanks
Flat cables are never a good thing. Round 100% copper cat5e or cat6a with 22 to 24ga wire is best. I use monoprice cat5e cables -- https://www.amazon.com/Monoprice-Flexboot-Cat5e-Ethernet-Patch/dp/B00KWS7VZW/
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
Use only quality full copper cat5e and cat 6 cables. Cat 7 flatcables are a joke and worthless.

If a cable is questionable, it can sometimes autonegotiate 100mbps and other times 1000mbps with every restart.
Would this one be ok to use?

https://www.amazon.co.uk/World-Data-White-Network-Cable/dp/B003ZB7NCE/ref=sr_1_3?keywords=15m+cat5+ethernet+cable&qid=1657292547&refinements=p_72:419153031,p_n_feature_six_browse-bin:28251751031|28251755031&rnid=28251738031&s=computers&sprefix=15m+cat+5+e,computers,57&sr=1-3&th=1
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
That cable does not say that it is 100% copper and doesn't show the wire gauge.
This shows 100% copper and 24AWG -- https://www.amazon.co.uk/StarTech-com-Cat5e-White-Molded-Patch/dp/B008634Z7W
These show 100% copper but are 26AWG -- https://www.amazon.co.uk/15m-Professional-Network-Cable-enhanced/dp/B01HKV9FXY/

My choice of monoprice is available but selection is limited -- https://www.amazon.co.uk/Monoprice-Flexboot-Cat5e-Ethernet-Patch/dp/B00KXDGLSY/
Thank you I went with Star Tech hopefully will solve the issue, appreciate all the help you have given me!
 

gggplaya

Distinguished
That cable does not look very good and most likely CCA(Copper Clad Aluminum). It also states 10/100 as well, at least they're up front about that. Probably from a history of complaints about the cable.

I don't see any reputable cable manufacturers on Amazon UK, which boggles my mind, and I see a ton of junk flatwire cable which is crazy. No wonder so many people in the UK have issues with their ethernet. I guess since most of the country is on FTTC and can only get 80mbps internet speeds, it hasn't shown it's face until now. For 15 meters, I would only do pure copper, I would not do CCA at those distances.

Monoprice is a reputable brand, and this cable is pure copper. But only yellow is in stock at 50ft(15meters): https://www.amazon.co.uk/Monoprice-Flexboot-Cat5e-Ethernet-Patch/dp/B00KXHFVK4
 

vamosuk

Commendable
Feb 23, 2020
16
0
1,510
0
That cable does not look very good and most likely CCA(Copper Clad Aluminum). It also states 10/100 as well, at least they're up front about that. Probably from a history of complaints about the cable.

I don't see any reputable cable manufacturers on Amazon UK, which boggles my mind, and I see a ton of junk flatwire cable which is crazy. No wonder so many people in the UK have issues with their ethernet. I guess since most of the country is on FTTC and can only get 80mbps internet speeds, it hasn't shown it's face until now. For 15 meters, I would only do pure copper, I would not do CCA at those distances.

Monoprice is a reputable brand, and this cable is pure copper. But only yellow is in stock at 50ft(15meters): https://www.amazon.co.uk/Monoprice-Flexboot-Cat5e-Ethernet-Patch/dp/B00KXHFVK4
Ok thank you changed to the monoprice cable will take a while to come but I suppose I might as well wait it out.

THank you again!
 

gggplaya

Distinguished
Ok thank you changed to the monoprice cable will take a while to come but I suppose I might as well wait it out.

THank you again!
Ebay might be a better option: https://www.ebay.co.uk/itm/351802466526?var=620710048861 This shop doesn't sell a branded cable, but seems to reiterate the fact that most cables sold on the internet are fake or don't meet specifications. Claims their cable is legit 24awg solid copper.
 

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