Performance Issue with 1 Gigabit an Router RT-AC68U

[Doppel Moppel]

Hi together,

I wanted to ask you if you can help me with a performance problem with an Asus RT-AC68U router.

In concrete terms, I switched to a new subscription model because my provider offers considerably higher speeds for a very low surcharge.

The prerequisites would be as follows:

- FTTH glass fibre up to the house
- Speed: 1 Gigabit
- Cabling from the fiber modem to the router with cable cat. 7
- Cabling from the Asus RT-AC68U router to the PC with cable cat. 6
- In between a Zyxel Switch GS-108B v2 (8x, Gigabit)
- An onboard LAN from Intel Pro, also Gigabit on the PC
- PC-CPU is an Intel i7-2600 with 16 GB RAM
- Router Asus RT-AC68U (Firmware: Merlin 380.68_4)

Thus, the whole path of Internet data would actually be designed for Gigabit.

Now, however, it is the case that "only" approx. 480 - 520 MBit arrive.

I measured this using various speed tests that explicitly allow testing of 1 Gigabit connections.

I downloaded the test file into a large RAM disk, so that there should be no brake when saving. I also did several speed tests on various homepages, all of which have the same speed.

My specific questions are:
1) Does any of you guys have an Asus RT-AC68U router in use and successfully operates it at full speed at 1 Gigabit?
2) If yes, what else would you have to set up differently or adapt which infrastructure in order for the full 1 Gigabit to get through?
3) Is it possible that the Asus RT-AC68U is no longer able to manage this 1 Gigabit in terms of performance?
4) Is there any of you using another router (preferably from Asus) that allows the full 1 Gigabit?

Thank you for your feedback and support.

Regards,
Doppel Moppel

 

[NoSync]

On OpenFiber Italy network, my RT-AC68U is hooked up directly to the FTTH media converter and connects through PPPoE, getting consistent wired speeds of over 900 mbit/sec. Make sure HW acceleration is enabled, otherwise that'd explain the low speeds you're getting.

 

[Milanche]

Hi together,

I wanted to ask you if you can help me with a performance problem with an Asus RT-AC68U router.

In concrete terms, I switched to a new subscription model because my provider offers considerably higher speeds for a very low surcharge.

The prerequisites would be as follows:

- FTTH glass fibre up to the house
- Speed: 1 Gigabit
- Cabling from the fiber modem to the router with cable cat. 7
- Cabling from the Asus RT-AC68U router to the PC with cable cat. 6
- In between a Zyxel Switch GS-108B v2 (8x, Gigabit)
- An onboard LAN from Intel Pro, also Gigabit on the PC
- PC-CPU is an Intel i7-2600 with 16 GB RAM
- Router Asus RT-AC68U (Firmware: Merlin 380.68_4)

Thus, the whole path of Internet data would actually be designed for Gigabit.

Now, however, it is the case that "only" approx. 480 - 520 MBit arrive.

I measured this using various speed tests that explicitly allow testing of 1 Gigabit connections.

I downloaded the test file into a large RAM disk, so that there should be no brake when saving. I also did several speed tests on various homepages, all of which have the same speed.

My specific questions are:
1) Does any of you guys have an Asus RT-AC68U router in use and successfully operates it at full speed at 1 Gigabit?
2) If yes, what else would you have to set up differently or adapt which infrastructure in order for the full 1 Gigabit to get through?
3) Is it possible that the Asus RT-AC68U is no longer able to manage this 1 Gigabit in terms of performance?
4) Is there any of you using another router (preferably from Asus) that allows the full 1 Gigabit?

Thank you for your feedback and support.

Regards,
Doppel Moppel

You won’t believe but I have exactly same config (except that switch is D-Link) and exactly the same problem!((
With the ISP speed connected directly to PC I get 650/650 Mbps but through ASUS the speed drops to 220/480((
I got speed drop both wired or wireless.
I run latest Merlin firmware but it was the same on original Asus firmware. Regardless of QOS or network acceleration on/off there is no difference.
On the other hand- when I download something in local network - for example huge movie from Synology nas to my pc - I got very fast speeds about 100 Mbytes/sec.
I’ve searched the internet and it’s full of this kind of complains.
Any ideas..?

 

[Doppel Moppel]

Hi together,

I wanted to ask you if you can help me with a performance problem with an Asus RT-AC68U router.

In concrete terms, I switched to a new subscription model because my provider offers considerably higher speeds for a very low surcharge.

The prerequisites would be as follows:

- FTTH glass fibre up to the house
- Speed: 1 Gigabit
- Cabling from the fiber modem to the router with cable cat. 7
- Cabling from the Asus RT-AC68U router to the PC with cable cat. 6
- In between a Zyxel Switch GS-108B v2 (8x, Gigabit)
- An onboard LAN from Intel Pro, also Gigabit on the PC
- PC-CPU is an Intel i7-2600 with 16 GB RAM
- Router Asus RT-AC68U (Firmware: Merlin 380.68_4)

Thus, the whole path of Internet data would actually be designed for Gigabit.

Now, however, it is the case that "only" approx. 480 - 520 MBit arrive.

I measured this using various speed tests that explicitly allow testing of 1 Gigabit connections.

I downloaded the test file into a large RAM disk, so that there should be no brake when saving. I also did several speed tests on various homepages, all of which have the same speed.

My specific questions are:
1) Does any of you guys have an Asus RT-AC68U router in use and successfully operates it at full speed at 1 Gigabit?
2) If yes, what else would you have to set up differently or adapt which infrastructure in order for the full 1 Gigabit to get through?
3) Is it possible that the Asus RT-AC68U is no longer able to manage this 1 Gigabit in terms of performance?
4) Is there any of you using another router (preferably from Asus) that allows the full 1 Gigabit?

Thank you for your feedback and support.

Regards,
Doppel Moppel

===================================================

Hi NoSync

Thank you so much for telling me.

I checked it in my router settings and the hardware acceleration was already enabled there.

Then I continued my research on the Internet and came across the following URL:

https://routerguide.net/generic-optimization-guides/

In accordance with these instructions, I then implemented a number of suggestions for improving performance. The speed then increased to approx. 530 to 560 MBit.

Much better, but still far away from 1000 MBit.

I will now try to connect the LAN cable directly to the PC without a switch. If the speed increases massively, the switch would be the cause of the throttling.

If that's the case, can someone recommend a Gigabit switch that delivers full performance, or is this not possible with SoHo devices? Do you have to switch to professional devices?

Would it do any good to switch to a stronger router? E. g. the Asus RT-AC88U or RT-AC5300?

Thank you for your feedback.
Regards
Doppel Moppel

P.S.: The translation was done with www.deepl.com. Great!

 

[b00st88]

Hi, try following:

disable QOS
*disable* Spanning Tree Protocol *corrected from enabled*

and watch in the GUI the CPU usage during a big download when it's permanent 95-100% your CPU from the Router is to low to handle big traffics like this.

Im in Switzerland with also a 1Gbit Connection via Fiber after Enabling STP the speed increases massivly.

I saw your post and sign up instantly

 

[b00st88]

And please to test it right go to

http://www.dslreports.com/de/speedtest

register quickly and Enable 1Gbit support

then test it again with the Fiber Pre-configuration there.

and post your results here

 

[b00st88]

I have a AC88u with bigger cpu and most important the max. WAN throughput is around 1.6Gbit im not sure if the ac86u can handle your speed.

 

[Doppel Moppel]

Hello everyone.
I have now carried out several tests with various Speedtest homepages.
The results are phenomenal but also difficult to understand.

1) QoS = OFF is the most effective option!
QoS = OFF activates the entire hardware acceleration ==> CTF (Cut Through Forwarding) and FA (Flow Acceleration) accelerators are activated.
2) STP (Spanning Tree Protocol) ON or OFF does not make any big difference.
3) The utilization of the CPU with QoS = OFF decreases extremely from approx. 80 % to approx. 3 - 4 %. Super!
4) It depends extremely on which homepage you choose for the speed test!
Here are a few examples:
http://beta.speedtest.net/result/6695540030
http://www.dslreports.com/speedtest/23152228
Here the differences between the speed tests are so enormous that I can't explain it.

I have done all my previous speed tests with http://beta.speedtest.net
And here the increase is enormous! It seems that the QoS swallows up so much resources that the speed for down/upload is massively impaired.

Since I'm not a big gamer, this is okay for me.

But if gaming is important, you probably have to turn the QoS back on. Correspondingly poor down/upload results.

I will now leave it at that and am happy to have found the right attitude for me.

Thanks to all for your support!

salutation
Doppel Moppel

 

[Milanche]

And please to test it right go to

http://www.dslreports.com/de/speedtest

register quickly and Enable 1Gbit support

then test it again with the Fiber Pre-configuration there.

and post your results here

YYYYYYYYYYEEEEEEEAAAAAAAAHHHHHHH!!!! (I've changed my internet plan to 300/300 since I didn't want to pay for speeds that I don't reach)
The STP protocol was ENABLED. Regardless of QoS on or off, speed didn't change. But I just tried to turn STP off - AND IT WORKED!!!)))
The speeds here http://www.dslreports.com/de/speedtest with STP ON were 234/353, and with STP OFF they went to 307/505 !!!!!!!! WOW!!!! (beta.speedtest.net is showing 320/610!!!)
And only after turning OFF STP and QoS - under NAT acceleration in Auto mode I see status - CTF (Cut Through Forwarding) and FA (Flow Acceleration) accelerator are enabled.
Problem solved!
P.S. By the way - during test only one processor core got loaded and maximum it got to 80%. Mostly it was about 30-50% of load.

 

[Milanche]

 

[doczenith1]

My 68U can routinely hit 940 Mbps up and down. Core 1 will hit 100% cpu usage during the test. I have only CTF enabled and not FA. I run a pretty basic setup the following options changed from the defaults. I have read on this site that PPPoE can cause speed problems with a FTTH connection. I didn't see any mention of your connection type but if it is PPPoE I would recommend searching this site for related threads.

AiProtection - Network Protection
All options on

Wireless 2.4 GHz Professional
Turbo QAM - Disable
Airtime Fairness - Disable
Explicit Beamforming - Disable
Universal Beamforming - Disable

Wireless 5 GHz Professional
Airtime Fairness - Disable
Universal Beamforming - Disable

LAN - DHCP Server
Two wired computers with Manually Assigned IP

LAN - Switch Control
Enable Jumbo Frame - Disable (can’t remember if this is the default or not)
Spanning-Tree Protocol - Disable

WAN - Port Forwarding
Two wired computers with port forwarding.

 

[Milanche]

This is the WiFi 5Ghz speed with my iPhone 7 through two brick walls.))
Looks nice. I think I’ll switch back again to 650/650 speed contract))

 

[Doppel Moppel]

Hello, Milanche.
According to your information you are faster than 99% of all users in Russia: -)
That's great, isn't it?
In any case, I am now also satisfied with my configuration.
I don't get to the full 1000 MBit permanently, but for me it's perfect enough now.
What surprises me, however, are the large bandwidths of the displayed speeds, depending on which Speedtest homepage you visit.
Well, yeah. The main thing is that with a few clicks in the router the speed could be increased noticeably.
Because you can never have enough speed, can you?

Salutation
Doppel Moppel

 

[b00st88]

Sorry I have to correct it i mean STP disable give me more DL speed at the end like 100-150mbit more insteat 650-700mbit but upload is still around max. 930-960mbit.

ok I have to say Im ajusting in everywhere Win10 Internetservices etc. and Network Controller also with differenz parameters for better flow, less lag, more accurate in tcp/udp games. Could be placebo but it feels a little bit smoother. If someone interested I can post the settings.

 

[b00st88]

One point that I don't unterstand is "Bufferbloat" with a fiber connection before that I know how to ajust it right for 0% Bufferbloat but now seems like no Setting works like before over vdsl2.

 

[Doppel Moppel]

Hello b00st88,

If you have an Asus router, I would be interested in your parameters!

I have also found some of the below mentioned. Guide and found that this brought a lot of performance! For example, in the firewall, turning off Flood Attack Detection. QoS = OFF, etc.

https://routerguide.net/generic-optimization-guides/

I've done it all for me, the QoS services, which I shut down completely. Afterwards the down- and upload was noticeably better.

I can't say if you have to switch on STP at all in the home area. From the guide it has been found out that there are mainly would be something for larger environments and avoids data loops. With the two switches I use for myself, it won't do much good.

It is important to me to achieve a good mix of speed and stability.

Netflix streams, Youtube videos and "heavy downloads" often run at the same time.

I don't know if you have the right device for 1 Gigabit with a simple router like the RT-AC68U.

If this device turns out to be too weak, I will upgrade to a stronger router.

salutation

 

[doczenith1]

I don't know if you have the right device for 1 Gigabit with a simple router like the RT-AC68U.

If this device turns out to be too weak, I will upgrade to a stronger router.

salutation

Again...my 68U can routinely hit 940 Mbps up and down. I have also verified those speeds while downloading torrents so not just on speed tests. If you're not running a bunch of other services on the 68U then it will handle a gigabit connection albeit at 100% cpu usage.

 

[tuomi]

After fiddling with CTF_FA, STP, overclocking etc. I solved my issues by disabling asusnat_tunnel under Tools, Other settings, almost at the bottom.

 

[R1-Limited]

Holy crap 2 years later and boom, 1 gig after turning off spanning tree Who'd a thunk. I just turned up 1gig from ziply and found crap for performance. Turned off spanning tree and BOOM

 

[Atais]

Hey.
I stumbled upon this thread while googling what might be the reason of poor performance of my AC68U.

All in all, it turned out my corporate laptop has some security filters and it just cannot use full 1gbps!

But in the meanwhile I managed to tweak the settings a bit and thanks to @doczenith1 and @tuomi
The highest 940/300 score (on the other laptop) I got with:

• QoS off
• LAN - Switch Control
  Enable Jumbo Frame - Disable
  NAT Acceleration - Auto (it shows CTF is enabled)
  Spanning-Tree Protocol - Disable
• Tools - Other settings
  Memory Management - Yes
  Firewall - No
  Wan - No
  Disable Asusnat tunnel - Yes (extra 10-20mbps)
  dhcpd - Yes

I did not play with WiFi settings because you won't get full speed this way anyway and some of those legacy settings sound useful after googling.