Asus RT-AX89X slow down internet speed - 10G become 1.8G and can only connect to modem via SFP+ and not RJ45

DKuo

Occasional Visitor
Hi everyone, need your advice - wonder anyone experienced significant drop in internet speed via RT-AX89X? I have a 10G fibre connection (provided by Netvigator in Hong Kong) and I get anywhere between 8.5 to 9.8Gbps if I connect my desktop computer directly to modem via RJ45, however, once I connect via RT-AX89X, the speed drop to 1.5 to 1.8Gbps. Also, I cannot connect the RT-AX89X to modem via RJ45 port, only via SFP+ port (even after I change the WAN setting), just wonder if anyone experience the same and any solution?

Thanks for your advice in advance and please stay safe and healthy.

Best regards

DK
 

itpp20

Senior Member
That is a the maximum speed for a single connection (wired/wifi), it specs lists 10g as total/combined, not for one port.
Ea. you can have 9x1.3-1.8g connections (depending if the 10g port can handle this total load)
 

DKuo

Occasional Visitor
Thanks for your explanation, so if I understand that correctly, I should just connect the RJ45 directly from modem to the computer to take full advantage of the speed then, right? Given WiFi will never achieve that kind of bandwidth, I should get a 2.5GB internet connection to connect to a WiFi router for WiFi then, that will be more efficient use of resources instead of having a 10G but only really use 1.8max for the computer I really need to use it, is my understanding correct?
 

Tech Junky

Very Senior Member
10GE + Asus = Fail

If you want those kind of speeds you'll need to reimagine things a bit.

ISP <> 10GE Router <> 10GE switch <> AX / AX-E AP's

or go DIY with a PC w/ 10GE NIC dual port to a switch for clients + AP's

I setup a DIY + AP and WIFI clients internally hit up to 1.5gbps and that's a limitation of the current WIFI standards. WIFI will continue to under perform until potentially WIFI7 comes along.

You could do a 2.5GE setup if it's more cost effective on the ISP side to make it worthwhile or going wired @ 2.5 or 5GE cheaper than the full 10GE. Aggregate multi device speeds could hit 10GE speed though. It depends on how many clients and the workload needing to be sent cross the line.
 

CBme

Occasional Visitor
Thanks for your explanation, so if I understand that correctly, I should just connect the RJ45 directly from modem to the computer to take full advantage of the speed then, right? Given WiFi will never achieve that kind of bandwidth, I should get a 2.5GB internet connection to connect to a WiFi router for WiFi then, that will be more efficient use of resources instead of having a 10G but only really use 1.8max for the computer I really need to use it, is my understanding correct?
No, the information given is incorrect and not applicable for the problem you described as you are talking about wired speeds and an issue with the RJ45 10gbit port not working for WAN. Not sure why WIFI was brought into the discussion (unless you are saying that the 1.8gbit test result is a WIFI connection to the computer, which would be insanely/impossibly great speed to a single wifi6 5ghz device if that is the case). You should be able to use either the rj45 or the SFP+ port for full 10gbit WAN connection and use the other port for full 10gbit speed to your computer (assuming your computer has a 10gbit NIC which you obviously do).

This is the only router recommended by our ISP who provides 2 & 5gbit service (I'm in the US) so folks around here have used it extensively and I can confirm that both ports work at full speed for both service levels as it has been discussed by other users in the reddit forum for the ISP. While I can't test 10gbit WAN, it does a full speed 10gbit transfer across the LAN. For my current 2gig service I get the exact same speedtest.net speeds (2.1gbit up and down) whether plugged into the PC directly or through the router. I input to my RJ45 for WAN, out via SFP Direct Attach cable to a 10gbit MicroTik and then out to my computer via a SFP+ RJ45 module. I've both ports for WAN, with the other going directly to my computer and didn't see a difference. Review confirming it can do 10gbit throughout without an issue: https://dongknows.com/asus-rt-ax89x-review/

So you should not be seeing the issues you are mentioning. The only question I have is what are you using to determine that you are only getting 1.8gbit speeds through the AX89X? Here, I would say to ensure that you are using the speedtest.net app, not web page, and selecting a server that you know can do the full speed, for the tests (don't use the internal test in the AX89). Not sure what the best tool or site for WAN speed tests is there.

As for it not working through one port, that could point at the bigger issue and could relate to why the other is only giving you 1.8gbit (if that is correct). It could indicate some compatibility issue with your ISP (though that would be strange). Only recommendation I'd have here is to ensure your firmware is updated and if it is, reach out to the ISP and Asus to see if there is compatibility issues they are aware of.
 
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danceedance

Occasional Visitor
No, the information given is incorrect and not applicable for the problem you described as you are talking about wired speeds and an issue with the RJ45 10gbit port not working for WAN. Not sure why WIFI was brought into the discussion (unless you are saying that the 1.8gbit test result is a WIFI connection to the computer, which would be insanely/impossibly great speed to a single wifi6 5ghz device if that is the case). You should be able to use either the rj45 or the SFP+ port for full 10gbit WAN connection and use the other port for full 10gbit speed to your computer (assuming your computer has a 10gbit NIC which you obviously do).

This is the only router recommended by our ISP who provides 2 & 5gbit service (I'm in the US) so folks around here have used it extensively and I can confirm that both ports work at full speed for both service levels as it has been discussed by other users in the reddit forum for the ISP. While I can't test 10gbit WAN, it does a full speed 10gbit transfer across the LAN. For my current 2gig service I get the exact same speedtest.net speeds (2.1gbit up and down) whether plugged into the PC directly or through the router. I input to my RJ45 for WAN, out via SFP Direct Attach cable to a 10gbit MicroTik and then out to my computer via a SFP+ RJ45 module. I've both ports for WAN, with the other going directly to my computer and didn't see a difference. Review confirming it can do 10gbit throughout without an issue: https://dongknows.com/asus-rt-ax89x-review/

So you should not be seeing the issues you are mentioning. The only question I have is what are you using to determine that you are only getting 1.8gbit speeds through the AX89X? Here, I would say to ensure that you are using the speedtest.net app, not web page, and selecting a server that you know can do the full speed, for the tests (don't use the internal test in the AX89). Not sure what the best tool or site for WAN speed tests is there.

As for it not working through one port, that could point at the bigger issue and could relate to why the other is only giving you 1.8gbit (if that is correct). It could indicate some compatibility issue with your ISP (though that would be strange). Only recommendation I'd have here is to ensure your firmware is updated and if it is, reach out to the ISP and Asus to see if there is compatibility issues they are aware of.

in your links, i see another user having problem reaching 10G.

Do we need to try changing the settings from auto to 10G in Lan/Switch Control menu?

Hi again Dong,

I bought he RT-AX89X after commenting on the GT-AXE11000 in your WiFi 6 article. Just want to pick your brain for any possible advice. I have been going back and forth with Asus support here in Japan for almost half a year and they still can’t figure out what is wrong. When I set the RT-AX89X up in router mode, I only get about 3 Gbps on my 10Gbps plan—way slower than expected. In AP mode, connected to the basic router provided by my ISP, I get over between 7.5 and 9Gbps. I don’t really need that much speed, but it is nice to know I am getting the speed I am paying for. I may be jumping to conclusions, but seeing that none of the newer Asus routers have 10G ports on them, could it be that Asus is suffering from some type of problem with 10Gbps in router mode like I am experiencing? Any thoughts from you Dong, or from anyone reading this who also has this router and a 10Gbps internet connection would be greatly appreciated. Best regards, Robert
 

CBme

Occasional Visitor
in your links, i see another user having problem reaching 10G.

Do we need to try changing the settings from auto to 10G in Lan/Switch Control menu?
Certainly wouldn't hurt to test that. Though that user being in Japan and having a US model adds a little to the thought that there may be some strange incompatibility with it and your ISP in Hong Kong. Unfortunately I don't have any other insight that would help any more than you just testing settings. Only thing I can say is that it should be giving you full speed you expect.
You could also check on Asus's forums in addition to contacting them and your ISP to see if they are aware of any known issues with this model and the service there.
 

DKuo

Occasional Visitor
Thanks for everyone’s advice, is it common to have incompatibility issue with ISP in different part of the world? Is there difference in RJ45 connection? Have to admit I find it extremely strange that the RT-AX89X will not detect the RJ45 10G connection but no problem if I use the SFP+ port. That‘s the case even after I change the configuration to RJ45 in the settings for WAN. I’ve double tested all the cables to make sure they are working properly. As I have a few RT-AX89X in my AiMesh settings, I am going to swap some and reset them and test the setup again and see if that makes any difference. May I ask are you aware of any diagnostics to make sure the router is fully functioning properly please?

Thanks again everyone, while it‘s frustrating not getting the full speed, its actually great to learn from all you experts, will try different setup and come back with the result.
 

itpp20

Senior Member
When it comes to performance these are more realistic numbers:

Looking at the specs its nothing new other then better hardware/antenna's:

Second, a RJ45 was never made to handle 10g, what Asus has done is a hack asking for problems, stick to SFP if you want wired 10g speeds. If you want real 10g LAN speed wired, have someone add a SFP port.
 

danceedance

Occasional Visitor
I think asus is using qualcomm reference hawkeye platform, as i seen it has x2 10G USXGMII interfaces, so RJ45 should work



 

CBme

Occasional Visitor
When it comes to performance these are more realistic numbers:

Looking at the specs its nothing new other then better hardware/antenna's:

Second, a RJ45 was never made to handle 10g, what Asus has done is a hack asking for problems, stick to SFP if you want wired 10g speeds. If you want real 10g LAN speed wired, have someone add a SFP port.
There is nothing in that Tweaktown testing that deals with the OP's issue of 10gbit LAN, and more specifically, the 10 gig WAN connection. They only test the 1gig LAN and the wireless speeds, neither of which are relevant for this issue.

As for RJ45 and 10gig, that is silly as yes, the connections are "designed" to handle 10gig (officially supported via cat 6 and higher cables) and are literally rated and tested for it and have been in widespread use in enterprise for many, many years. There is no "hack" Asus is doing to make 10gig work as it is standard product from hundreds of other manufacturers who make consumer and enterprise level 10gig RJ45 products. You can even do 40gig via rj45/copper (cat 8 cable) as that official specification was finalized 6 years ago. As for whether to prefer optical cables SPF+ or RJ45 for home setup, that is a subject of different discussions and doesn't have to do with this thread about the OP's WAN issue when using this device vs plugging into his 10gig rj45 port on his PC directly.
 

Starrbuck

Senior Member
I have 10gig WAN from my ONT to the router using RJ-45, and 10gig LAN from the router to a QNAP QSW-M408-4C switch using SFP+ (DAC cable). No issues with speeds. My actual Internet rate is 2gig but I have a solid 10gig on the status screen for WAN.
 

DKuo

Occasional Visitor
I finally got time to swap the router and test, managed to get 8GB after I swap the A1 with an A2 rev model and it work so it seems there‘s something wrong with the router. However, even with the A2 rev model still has to use SFP+ to connect to the router from modem, just cannot do it via RJ45 (I can live with that). Thanks so much for everyone’s help, really appreciated. Happy Easter, everyone!
 

RTWZ80

Regular Contributor
Sorry for the super belated post, but are you running VPNs through the router? I have 10Gbps broadband on an active optical network. The SFP+ port is used as WAN and the 10GBase-T port goes to a QNAP 10GbE unmanaged switch where the rest of the home network is linked. With VPNs like IPSec or Asus' own InstantGuard on, my wired speeds as tested on Ookla drop to the +1Gbps range. Turn them off and wired speeds return to the 8-9 plus Gbps range. Also, have you tried enabling Jumbo Frames in the LAN-Switch Control tab in the web GUI? That seems to help particularly with 10Gbe networking. Enabling AiProtection may also throttle broadband speeds, but in my case, the impact is minimal.
 

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