What's new

RT-AX86U Speedtest

  • SNBForums Code of Conduct

    SNBForums is a community for everyone, no matter what their level of experience.

    Please be tolerant and patient of others, especially newcomers. We are all here to share and learn!

    The rules are simple: Be patient, be nice, be helpful or be gone!

gp-se

Regular Contributor
When I use the internal speed test in the Adaptive QOS settings page it always maxes out around 620-630 Mbps. If I use my browser and go to the Ookla speed test page and select the exact same test server I get closer to my actual speed (Gigabit). Anyone else notice this? I have a RT-AX86U with firmware 3.0.0.4.388_22068.
 
Built-in speedtest may be hardware limited depending on what options you have enabled in firmware. This is well known effect and speedtest result may not be accurate above 500Mbps ISP connection. Use wired client instead.
 
Why would it be hardware limited only using the built in speed test? Wouldn't a hardware limitation result in the browser speed test also being limited since its going from: Computer ->AX86U-> Internet.
My internet plan is 1.5 Gigabit, so using my Computer the speed test will max out at Gigabit, that's why I wanted to use the internal app since I use the 2.5G port as WAN.
 
Why would it be hardware limited only using the built in speed test?

Because it is and you're not the first one to find out and ask this question. Report the issue to Asus in Administration, Feedback form.
 
Why would it be hardware limited only using the built in speed test?
The CPU in these routers (not only ASUS', but most other consumer-grade gear) is not remotely capable of passing data at full line speed. Instead, forwarding packets from one place to another is handled by specialized hardware that can reach the advertised speeds, at least when dealing with requirements within its capabilities. But the speed test is done by the CPU and is limited by how fast it can transfer data to/from the networking hardware.
 
This is not NAT acceleration related. This router can't do above 400Mbps with NAT acceleration disabled. I guess @gp-se has TrendMicro components enabled affecting the speedtest. I would disable all TrendMicro components (Administration, Privacy - Withdraw data sharing agreement) and test again.
 
This is not NAT acceleration related. This router can't do above 400Mbps with NAT acceleration disabled. I guess @gp-se has TrendMicro components enabled affecting the speedtest.
Hmm ... @gp-se reported getting gigabit-ish speedtest results from a connected computer, so that seems to show that none of the NAT-acceleration-blocking features are enabled. I still think the issue is what I said, that is the CPU can't manage 1Gbps speeds for its own transfers. I've not tried this sort of thing on ASUS hardware, but I've seen exactly this behavior on my Ubiquiti EdgeRouter-X gear: the router can pass data from port A to port B at 1Gbps line speed, but if you try to test it using the internal iperf3 client/server, it maxes out at a good deal less than that.
 
All TrendMicro stuff is disabled. I think @tgl is correct that the internal CPU can't process the data, but has no problem passing the packets to the connected devices.
 
Just another not needed and buggy bloatware in Asuswrt. Arrived somewhere around 386 firmware uninvited. Ignore it.
 
QoS speediest result is around 890-900mbps and real speed on ookla or fast is 945 Mbps
 
I have an RT-AX86U connected to modem via link aggregation. With a 1Gb plan (and 20% over-provisioning), I test using the internal speed test between 1050 and 1100 Mb. QoS inactive. Merlin firmware.

tests.jpg
 
Last edited:
Here are some results obtained on my AC86U. Had some Linux distros downloading which slowed down the speeds a little on the recent test.

1675896856969.png
 
So you guys can all get faster speed test results than me, this is weird. I don't understand why in the GUI I cannot get faster than 630Mbps, but using my computer I get 900+
 
If you have been toggling options on/off, note that that is not the same as leaving (some) of those options off in the first place. You may need to do a full reset, without using any saved backup config files afterward, to get the router back to a good/known state.

Before you do that full reset to factory defaults though, try going to the Administration, Privacy tab and Withdraw from all permissions you've previously granted. Afterward, be sure you reboot, then verify you've actually withdrawn too.
 
In Privacy I have no permissions/nothing to withdraw, I never used any of the TrendMicro stuff. I'm a very basic user, so most settings are at default, with the exception I use custom DNS servers (Cloudflare).
 
So you guys can all get faster speed test results than me, this is weird. I don't understand why in the GUI I cannot get faster than 630Mbps, but using my computer I get 900+
Run top -d1 in the router’s ssh session and watch the idle percentage (the number to the left of the word “idle”). Press the number 1 key to show all CPUs individually in top.

Run the router speedtest in the GUI. Watch the idle percentages in SSH. If any CPU reaches 0% idle, you have a CPU limitation for the ookla utility on the router.

1675989035914.png
 
Last edited:
I figured it out guys, once I disabled ipv6 on the router I was able to get full speed test results.
 

Latest threads

Support SNBForums w/ Amazon

If you'd like to support SNBForums, just use this link and buy anything on Amazon. Thanks!

Sign Up For SNBForums Daily Digest

Get an update of what's new every day delivered to your mailbox. Sign up here!
Top