AC68U - (UK - Vodafone, Cityfibre) only 300Mbps downstream on gigabit line

[ianyp]

With the vodafone router I get 900+ Mbps downstream.

...But if I use my AC68U in its place and doing a speed test from the router itself I get only 1/3rd of that (slightly more than that upstream consistently for some reason). QoS is disabled - I even checked it was disabled in NVRAM.

I'm using PPoE to authenticate. Cityfiber needs you to have VLAN 911 set which I did through the IPTV page. Are there any other settings that could cause this?

The CPU seems to max out during the speedtest - I overclocked the CPU but the result stays *exactly* the same.

Is this model just not gigabit capable?

I even daisy-chained them together.....

fiber <-> vodafone <-> ac68u

and ran the speed test again with the same result making me think it's just not powerful enough.

 

[bennor]

and doing a speed test from the router itself I get only 1/3rd of that (slightly more than that upstream consistently for some reason).

Incorrectly reported speed test results when running the router's speed test is a common complaint voiced elsewhere in this subforum (and others on this site) with some Asus routers, including the RT-AC68U. Run a speed test (https://www.speedtest.net/) from a wired PC and it should show more accurate results.

Edit to add: An example of the difference. Test when run from a RT-AC68U router on a 500/500 fiber line (no extras enabled like QoS or AiProtection):

Test when run from a PC connected to the RT-AC68U:

 

[capncybo]

With the vodafone router I get 900+ Mbps downstream.

...But if I use my AC68U in its place and doing a speed test from the router itself I get only 1/3rd of that (slightly more than that upstream consistently for some reason). QoS is disabled - I even checked it was disabled in NVRAM.

I'm using PPoE to authenticate. Cityfiber needs you to have VLAN 911 set which I did through the IPTV page. Are there any other settings that could cause this?

The CPU seems to max out during the speedtest - I overclocked the CPU but the result stays *exactly* the same.

Is this model just not gigabit capable?

I even daisy-chained them together.....

fiber <-> vodafone <-> ac68u

and ran the speed test again with the same result making me think it's just not powerful enough.

The CPU (& associated hardware) of that Router is not fast-enough to display correct information within the Router's WebGUI.
Plug in Your Fastest Computer via Ethernet to the router & Try a speed test from it's browser.
Then Get back to us with the result.
In short, that router cannot actually hit 1G but from memory I do think it can hit 800+

 

[ianyp]

I'm actually not using the web gui but the entware Okla speed test app. I have hooked up my laptop via ethernet and get the same result.

 

[ianyp]

All I could really find is this... I get the impression they don't know what they're talking about though.

How Do You Connect To CityFibre - PPPOE etc? :: Fibre Broadband :: think broadband

 

[bennor]

I'm actually not using the web gui but the entware Okla speed test app. I have hooked up my laptop via ethernet and get the same result.

What is the RT-AC68U's WAN port connected to upstream? A modem, another router, an ONT, just an Ethernet wire coming out of the wall? More information about your specific network configuration and broadband provider might help others determine where the issue may lie.

Edit to add: If your broadband provider provided the Vodafone router, maybe try cloning the Vodafone router's MAC address on the RT-AC68U. Might be a stretch, but could be the broadband provider is dropping the speed for non provider equipment MAC addresses. One can input the clone MAC address in the WAN > Internet Connection > Special Requirement from ISP > MAC Address field/section. Remember to hit the Apply button at the bottom of the page to save the settings. Might have to reboot the Asus router after cloning the MAC address.

Another value to check is the MTU number of the Vodafone router. Could be the Vodafone router uses a different MTU value and you have to use that same value on the Asus router's WAN MTU field (just below where one clones the MAC address).

 

[capncybo]

I'm actually not using the web gui but the entware Okla speed test app. I have hooked up my laptop via ethernet and get the same result.

Confusing statement because, I asked you to test on a fast computer that was wired to the router & you said...
"I'm actually not using the web gui but the entware Okla speed test app..."
But wouldn't a speed test app be on your phone or some other Wifi device?
But you also said...
"I have hooked up my laptop via ethernet and get the same result."
Fine but depending on the CPU & hardware of the Computer... they too can fail to display accurate 1G type speeds.
Regardless, I'll give you the benefit of the doubt because IMO,
All of the bloody advanced options which can dissable the routers Hardware Acceleration (Which will be needed to hit the speeds desired) are not obvious.
But STEP #1 should be...
Verify your HW acceleration has not been partially disabled.
Goto: Tools ->Sysinfo & look under the Network section for:
HW acceleration

You will need Hardware Acceleration to achieve the higher speeds you expect.

 

[rn170uk]

Hi,

Has anyone got to the bottom of this? I've just managed to get my RT-AC86U connected and I'm getting 200-300 instead of 900+. I've got VLAN 911 connected in the IPTV page, got my UID/PW configured right. HW Acceleration is enabled.

This post would imply it's possible to get decent speeds:

ASUS Zen Wifi XT8 - Setting up for Gigafast

All, I've just returned my Eero Pros to Amazon, and setup an Zen wifi in it's place, ready for Gigafast. With that in mind, I'm asking for a quick sanity check here - I need to get my PPPoE credentials (userid & password) plus the VLAN tag being used in my area from support. Anything else...

forum.vodafone.co.uk

 

[unsynaps]

I ca say for sure an RT-AC86U (at least at factory defaults) can get full speed on a 1G/1G connection without issue.

 

[Ripshod]

Administration>Privacy>Withdraw your consent then reboot. This will disable all the Trend stuff that's slowing the router down.
If that doesn't get you anywhere near close you may have an issue with vf/cf which is quite common.

 

[rn170uk]

iTried with THG3000 (Vodafone supplied router). Connected to LAN port - 910 down 920 up. (2nd test)
Tried with RT-AC86U. Connected to LAN port (though gigabit switch).
Edge: test 1
DOWNLOAD 250.70
UPLOAD 928.68
Edge test 2
331.87 / 928.48 (D/U)
Chrome: test 1 (same server chosen)
266.92 / 898.90 (D/U)
Chrome: test 2
440.30 / 912.94 (D/U)

 

[routeraround]

I have an AC68U connected to BT Fibre 500. The router speed test will never get above 320 Mbps. My desktop via Wifi has hit about 450.

 

[rn170uk]

Administration>Privacy>Withdraw your consent then reboot. This will disable all the Trend stuff that's slowing the router down.
If that doesn't get you anywhere near close you may have an issue with vf/cf which is quite common.

750 with that as measured at the router itself (QoS tab)

 

[Tech9]

Use a wired client for speed test. Built-in one can be CPU restricted.