Slow Ethernet Speeds on Asus Router

[Romanze]

Hello everyone, I am having some issues with my Asus RT-AC1750 Router. I have fiber optic 1 gbps internet, and directly connected I get about 900 down and up. The problem is when I bridge my modem to my router and directly connect that to my computer with a cat 6 cable, I can only get 500 down and 300 up. Here are some things I have tried.

1. Jumbo Frames Enabled (in router)

     Jumbo Frames 9kb MTU (network adapter settings)

2. Tried 2 cables, 1 being CAT 5e and the other CAT 6.

3. NAT Acceleration On and Off.

4. Firewalls On and Off (in router)

5. Speed & Duplex - 1 GBps Full Duplex (in Network adapter settings)

6. Updated firmware and then factory reset all settings.

There has been a few other things I tried, but did not list here. It is a 1GB router, and I get these speeds constantly when directly connecting to modem. Thanks ahead for the tips.

[Alex Atkin UK]

I'm not aware of any consumer router that can handle Gigabit.

 

When routers say they are Gigabit they are referring to the combined WiFi speed, not the broadband.

[Romanze]

7 minutes ago, Alex Atkin UK said:

I'm not aware of any consumer router that can handle Gigabit.

 

When routers say they are Gigabit they are referring to the combined WiFi speed, not the broadband.

This is a quote from Asus. Maybe I misunderstood? "Gigabit Ethernet ports for fast and reliable internet performance". To be clear I am not talking about wifi.

[Lurick]

2 minutes ago, Alex Atkin UK said:

I'm not aware of any consumer router that can handle Gigabit.

 

When routers say they are Gigabit they are referring to the combined WiFi speed, not the broadband.

Most Asus routers that have the AC-1750 name (that I could find) seem to hold up to about 800Mbps to 900Mbps LAN to WAN throughput but I'm not finding an "RT-AC1750" anywhere.

[Lurick]

16 minutes ago, Romanze said:

Hello everyone, I am having some issues with my Asus RT-AC1750 Router. I have fiber optic 1 gbps internet, and directly connected I get about 900 down and up. The problem is when I bridge my modem to my router and directly connect that to my computer with a cat 6 cable, I can only get 500 down and 300 up. Here are some things I have tried.

1. Jumbo Frames Enabled (in router)

     Jumbo Frames 9kb MTU (network adapter settings)

2. Tried 2 cables, 1 being CAT 5e and the other CAT 6.

3. NAT Acceleration On and Off.

4. Firewalls On and Off (in router)

5. Speed & Duplex - 1 GBps Full Duplex (in Network adapter settings)

6. Updated firmware and then factory reset all settings.

There has been a few other things I tried, but did not list here. It is a 1GB router, and I get these speeds constantly when directly connecting to modem. Thanks ahead for the tips.

Have you poked around in the settings and seen anything about performance counters?

[Romanze]

5 minutes ago, Lurick said:

Most Asus routers that have the AC-1750 name (that I could find) seem to hold up to about 800Mbps to 900Mbps LAN to WAN throughput but I'm not finding an "RT-AC1750" anywhere.

https://www.asus.com/us/Networking/RT-AC1750/

[Romanze]

5 minutes ago, Lurick said:

Have you poked around in the settings and seen anything about performance counters?

Like CPU and RAM monitors?

[Lurick]

1 minute ago, Romanze said:

https://www.asus.com/us/Networking/RT-AC1750/

Ok, so the real model is the RT-AC66U which is rated for LAN to WAN performance of about 850Mbps so you definitely should see some higher numbers. How are you testing? Speedtest?

 

 

1 minute ago, Romanze said:

Like CPU and RAM monitors?

I might be thinking of a different brand, let me poke around and double check.

[Romanze]

Speedtest.net app on Windows 7. Same results on the browser

[Alex Atkin UK]

Could Jumbo frames actually cause issues with broadband perhaps as the Internet is still limited to 1500?

[Lurick]

2 minutes ago, Alex Atkin UK said:

Could Jumbo frames actually cause issues with broadband perhaps as the Internet is still limited to 1500?

I'm thinking possibly that and/or QoS which is set to auto by default I believe. If that's on then perhaps OP can try turning it off and check with that off as well.

[Romanze]

I believe RT-AC66U and RT-AC1750 are two separate models.

[Alex Atkin UK]

I never even thought that QoS might be on by default, that's kinda bonkers considering the CPU overhead that causes.

 

I doubt QoS is even needed with Gigabit in most scenarios.

 

Personally though I'd use a PC and pfSense for a connection that fast.

[Romanze]

QoS is off now and also by default.

[Lurick]

1 minute ago, Romanze said:

I believe RT-AC66U and RT-AC1750 are two separate models.

-snip-

That's what's confusing me because if you look here:

https://www.asus.com/us/Networking/RT-AC1750/specifications/

 

It says the AC66U is in the box

 

[Alex Atkin UK]

Either way though, you aren't going to be getting your full speed out of that router.

Also bear in mind that if you use WiFi at any point that will slow it down even further by stealing CPU cycles from routing.  The ~850Mbit maximum speed is with the router doing WAN to LAN Wired and absolutely nothing else at the same time.

 

This is why I started using my old router for WiFi only and built a dedicated wired x86 router for broadband, as I saw WiFi alone saturating the router CPU and while I didn't notice any obvious impact on the broadband it was likely to manifest sooner or later.  It also allowed me to use QoS to drastically reduce my buffer bloat.

[Romanze]

Interesting Lurick. So, does anyone have anything else I can try?

[Lurick]

4 minutes ago, Romanze said:

QoS is off now and also by default.

There should be a menu for "Traffic Analyzer" on the main menu, is there anywhere in there to turn that off by chance?

[Romanze]

[Alex Atkin UK]

Well NAT acceleration will definitely need to be on and I'd try with jumbo frames off.  Maybe even turn WiFi off while testing to make sure nothing is connecting there.

[Romanze]

4 minutes ago, Alex Atkin UK said:

Well NAT acceleration will definitely need to be on and I'd try with jumbo frames off.

NAT Accel is on Auto (CTF enabled) jumbo frames is off.

[Alex Atkin UK]

Is there an option to force it On or just Auto?

[Romanze]

4 minutes ago, Alex Atkin UK said:

Is there an option to force it On or just Auto?

Unfortunately only Disable or Auto.

[Alex Atkin UK]

Do you connect to the WAN via DHCP or something like PPPoE?

The latter takes up yet more CPU power so would reduce the speed.

[Romanze]

Automatic, so I would assume that's DHCP.