RT-AX86U 2.5G port maximum is 1.3 Gbit/sec with iperf3

[shsch]

Router: Asus RT-AX86U
Router firmware: ASUSWRT-Merlin v386.2_2
Router operation mode: Wireless router
PC network adapter: TRENDnet 2.5GBASE-T adapter, TEG-25GECTX
Cable: Cat 6A 500 MHz

The router has a direct connection from 2.5G port to PC network card.
Why I get maximum of 1.3 Gbit/sec with iperf3 upload and download tests?
Where is the bottleneck?
Is this RT-AX86U router capable of 2.5 Gbits/sec?

By the way, if I switch to Access Point mode, the RT-AX86U network status of 2.5G port changes to 1 Gbps for some reason...

 

[ColinTaylor]

Slow LAN Performance Iperf3 RT-AX88u.

Hi All, New to this forum, I tried the latest build on my RT-AX88u 386.2. The update was painless, but I noticed the iPerf3 performance was very low. I tried Parallel Streams as well as adding a Window Size Parameter, but I wasn't able to go beyond 445Mbps. Am I missing anything? Currently...

www.snbforums.com

I don`t recommend running iperf3 on the router itself, as the router's CPU will become a bottleneck for iperf itself.

 

[shsch]

Slow LAN Performance Iperf3 RT-AX88u.

Hi All, New to this forum, I tried the latest build on my RT-AX88u 386.2. The update was painless, but I noticed the iPerf3 performance was very low. I tried Parallel Streams as well as adding a Window Size Parameter, but I wasn't able to go beyond 445Mbps. Am I missing anything? Currently...

www.snbforums.com

It's strange, but looks possible. Thanks.

 

[VIper_Rus]

It's strange, but looks possible. Thanks.

Hello. Have you sorted out the problem? I have exactly the same problem as you. Moreover, at the time of the test, the processor load is minimal

 

[KeithW]

Looks like the Iperf3 program running on the router itself has some restrictions.
I believe this is a restriction in the firmware itself. Because the router only has one 2.5 gig port the gateway firmware is restricting in one direction. If uploading when connected to the 2.5 gig port I am getting full speed. I tried this with other models that have more than one 2.5 port and this doesn't seem to be an issue with them.
Looks like a hardware restriction on the firmware side. I noticed when doing a speed test from the router using the WAN the restriction isn't there just for the LAN part of the router.
If you telnet into your router you do need Merlin firmware for this also a ISP with 2.5 Gig or higher service.
Use "iperf3 -c la.speedtest.clouvider.net -p 5207 -t 60 -V -b 0 -P 4" And you will see the ability to push out is at the 2.5 Gig switch limit. The firmware is restricting the other direction because the hardware itself is limiting it on the LAN side. Unless running the speed test using the built in speedtest software which will only engage the WAN so you can see download speeds to a single point at the 2.5 Gig limit. This limit, I am almost certain is because of the LAN hardware. Hope this helps. I believe you are getting the MAX Lan speed especially if you have the 2.5 gig port configured for the WAN.

 

[KeithW]

Hello. Have you sorted out the problem? I have exactly the same problem as you. Moreover, at the time of the test, the processor load is minimal

I think I sorted it out.