RT-AC5300 slow internet speed

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anshiyu

Occasional Visitor
Hi, guys

I'm having some slow internet speed issue with my RT-AC5300 router. Any suggestion is appreciated!

Here's the situation: I got xfinity 100MBPS internet. I have a Linksys CM3024 High Speed DOCSIS 3.0 24x8 Cable Modem. When I connect my computer directly to the modem, I am seeing the speeds I expect. About 100-110Mbps. I had xfinity guys to check my line, he confirmed I can get steady 120MPBS on my modem. However when I connect my computer to the AC5300, I get test results about 10-50Mbps but mostly seeing around 30MBPS.

I am using the latest stable Merlin firmware 384.12. I usually don't factory reset when upgrading firmware, but since the problem, I did the following:
1. gui reset to factory with Format JFFS partition at next boot
2.re-installed firmware 384.12
3.gui reset to factory with Format JFFS partition at next boot
4. hold reset button 30s then power off then on then release the button
5.re-installed firmware 384.12
6.gui reset to factory with Format JFFS partition at next boot

After these, I'm still getting around 30MBPS.

I tried change to another SSID after a re-install & reset, same.
I tried QoS, AIprotection and NAT acceleration on/off and the results doesn't change.

I also tried with an old router RT-AC87U on latest merlin, I can get 80~90MPBS on that with the same cable.

What can I do to increase my speed? I know the router AC5300 is the choke point right now, but I am not sure what I can change to make the speed more inline with what I should be getting.
 
Last edited:

ApexRon

Very Senior Member
However when I connect my computer to the AC5300, I get test results about 10-50Mbps but mostly seeing around 30MBPS.
Let me recap:
  • Xfinity 100Mbps service
  • PC Ethernet connection to cable modem yields speed of 100Mbps
  • PC connection to AC5300 yields speed of 30 Mbps
Questions:
  • What is the PC connection to AC5300?
    • If WiFi, then:
      • Please use Ethernet connection and report speed in a reply to this post
    • If Ethernet, then:
      • The speed of the Ethernet connection between the cable modem and the AC5300 should be reported as a steady 1Gbps on the AC5300.
        • If 1Gbps, then:
          • Please copy and paste your WAN configuration screen in a reply to this post
        • If not 1Gbps, then:
          • Possible Ethernet cable or physical cable connection issue. Check connections at each end and try using a different cable as well
          • Possible incompatibility with Auto-negotiation between cable modem and AC5300
            • Solution 1 - Set speed manually to 1Gbps on one side or the other. However, it looks like neither allow that to be done
            • Solution 2 - Place an Ethernet switch between that has set speed of 1 Gbps
            • Solution 3 - Cable modem from different company. I know my Netgear CM600 works with my AC86U
Let me know.
 

anshiyu

Occasional Visitor
Let me recap:
  • Xfinity 100Mbps service
  • PC Ethernet connection to cable modem yields speed of 100Mbps
  • PC connection to AC5300 yields speed of 30 Mbps
Questions:
  • What is the PC connection to AC5300?
    • If WiFi, then:
      • Please use Ethernet connection and report speed in a reply to this post
    • If Ethernet, then:
      • The speed of the Ethernet connection between the cable modem and the AC5300 should be reported as a steady 1Gbps on the AC5300.
        • If 1Gbps, then:
          • Please copy and paste your WAN configuration screen in a reply to this post
        • If not 1Gbps, then:
          • Possible Ethernet cable or physical cable connection issue. Check connections at each end and try using a different cable as well
          • Possible incompatibility with Auto-negotiation between cable modem and AC5300
            • Solution 1 - Set speed manually to 1Gbps on one side or the other. However, it looks like neither allow that to be done
            • Solution 2 - Place an Ethernet switch between that has set speed of 1 Gbps
            • Solution 3 - Cable modem from different company. I know my Netgear CM600 works with my AC86U
Let me know.
Thanks for your reply, let me answer your questions:
1. i'm using ethernet cable to connect PC and router, the same cable i connect between modem and PC to achieve 100MBPS.
2. YES the connection in Windows shows 1.0GBPS. I can copy file from my server at around 100MB/S, so the Lan part is working fine.
3. WAN settings are as follows:


Other settings are: No Dual Wan, No port trigger, no port forwarding, no dmz,
I am using asus DDNS for openVPN purpose
NAT:


Let me know if you need more info, thanks again!
 

ApexRon

Very Senior Member
I am using asus DDNS for openVPN purpose
For testing purposes only, consider disabling ASUS DDNS to see if that improves speed.

Further, unless your ISP requests it please change "DHCP query frequency" to Normal.

I have added two images. One is to show you the location of the "DHCP query frequency" option. and the other is to show you my speed for the Ethernet connection to my cable modem. Please confirm that your's is 1Gbps as well.
Screen Shot 2019-07-30 at 4.16.55 PM.jpg
Screen Shot 2019-07-30 at 4.22.15 PM.jpg
 

anshiyu

Occasional Visitor
For testing purposes only, consider disabling ASUS DDNS to see if that improves speed.

Further, unless your ISP requests it please change "DHCP query frequency" to Normal.

I have added two images. One is to show you the location of the "DHCP query frequency" option. and the other is to show you my speed for the Ethernet connection to my cable modem. Please confirm that your's is 1Gbps as well.
View attachment 18801 View attachment 18802

Hi, ApexRon

I changed DHCP query frequency to normal and did a quick test, no change.

I can confirm the ethernet port on router gui shows 1GBPS for both WAN and PC

For disabling DDNS test i have to do it after work, disabling it now means i can't get access my server through openvpn.
 

ApexRon

Very Senior Member
For disabling DDNS test i have to do it after work, disabling it now means i can't get access my server through openvpn.
Of course.

Another thought is IPv6. If enabled, consider disabling to test. Beyond that I am out of suggestions.
 

anshiyu

Occasional Visitor
Of course.

Another thought is IPv6. If enabled, consider disabling to test. Beyond that I am out of suggestions.
Thanks! I have one more question, did I do the fully restore to factory default part correctly? I tried to follow https://www.snbforums.com/threads/n...l-and-manual-configuration.27115/#post-205573

But as another post point out, should i also do a NVRAM clean up?
https://www.snbforums.com/threads/faq-nvram-and-factory-default-reset.22822/
it mentioned
  • Over SSH, you can run the "nvram erase" command.
  • Over SSH you can manually erase the nvram partition (do not use this method unless you know what you are doing! Erasing the wrong partition can permanently brick your router!) Run "mtd-erase nvram", followed by PHYSICALLY turning off then on the router. Do not use the reboot command.
Should I also do these 2 steps to fully restore the router?
 

ApexRon

Very Senior Member
Thanks! I have one more question, did I do the fully restore to factory default part correctly? I tried to follow https://www.snbforums.com/threads/n...l-and-manual-configuration.27115/#post-205573

But as another post point out, should i also do a NVRAM clean up?
https://www.snbforums.com/threads/faq-nvram-and-factory-default-reset.22822/
it mentioned
  • Over SSH, you can run the "nvram erase" command.
  • Over SSH you can manually erase the nvram partition (do not use this method unless you know what you are doing! Erasing the wrong partition can permanently brick your router!) Run "mtd-erase nvram", followed by PHYSICALLY turning off then on the router. Do not use the reboot command.
Should I also do these 2 steps to fully restore the router?
I am not familiar with any of that so I don’t want to give you bad advice on that. Hopefully, @ColinTaylor can answer.
 

ColinTaylor

Part of the Furniture
Should I also do these 2 steps to fully restore the router?
No don't do either of those (especially the second command!). They would only be useful if you couldn't log into the router's GUI and you didn't physically have access to the hardware reset button.

You only need to use one of the 4 methods mentioned in that post. Either of the first two are best:
If the router is booting correctly, then you can use any of the following:

  • While router is running, press the reset button for about 5 secs, then release it. Router will then reboot.
  • From the webui, on the same page where you can save/restore saved settings, there is a button to restore factory default values
 

anshiyu

Occasional Visitor
No don't do either of those (especially the second command!). They would only be useful if you couldn't log into the router's GUI and you didn't physically have access to the hardware reset button.

You only need to use one of the 4 methods mentioned in that post. Either of the first two are best:
Thanks! I already did restore factory default values from gui so restoring doesn't solve my problem......
 

anshiyu

Occasional Visitor
I switched back on the RT-AC87U on latest merlin firmware. Can achieve 110MBPS on my server.

I compared the WAN setting of both router, they are the same.

The only thing that hasn't been tried is clear NVRAM on the AC5300.. or is it possible some how the unit itself is mulfunctioned so it could't deliver more than 50MBPS?
 

ColinTaylor

Part of the Furniture
The only thing that hasn't been tried is clear NVRAM on the AC5300.
What do you mean? You've done that multiple times already. That's what the factory default reset does.
 

ColinTaylor

Part of the Furniture
if you click factory default "with initialize" then it should clear NVRAM.
Clicking on Restore clears the NVRAM. Clicking Initialize wipes jffs in addition to NVRAM.
 

ColinTaylor

Part of the Furniture
Isn't jffs part of NVRAM?
They're different partitions of the flash memory (aka NVRAM). So Asus are making a distinction here between the partition that stores the "nvram" variables and the partition that is used for /jffs. If "resetting nvram" wiped everything in the flash memory it would also wipe out the CFE and firmware.
 

Grisu

Part of the Furniture
yes thats what I meant!
Factory reset will reset NVRAM values (user configurations) to defaut and initialize will clear NVRAM, of course only those parts which could be changed by a user and not part of firmware.
 

ColinTaylor

Part of the Furniture
Factory reset will reset NVRAM values (user configurations) to defaut and initialize will clear NVRAM, ...
There is no difference between "resetting" nvram variables and "clearing" nvram. In both cases the router does an "nvram erase" which deletes all the nvram variables. When the router reboots the firmware recreates the nvram variables from the defaults stored in the CFE and firmware.
 
Last edited:

anshiyu

Occasional Visitor
Hi Guys,

I did another test, I brought the AC5300 to my office, I set it to AP mode and use ethernet cable to connect it to our main router, which is also a AC87U..

By wifi or ethernet cable connecting to this AC5300, I can achieve 110MBPS, which is maximum speed at our office.

I really wanted to switch my AC5300 in as the main router and test but everyone would be mad I cut the Internet....I don't know if the AC mode test means anything.
 

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