ASUS 5300 not getting gigabit speeds stuck at 100mbps - Centurylink

  • ATTENTION! As of November 1, 2020, you are not able to reply to threads 6 months after the thread is opened if there are more than 500 posts in the thread.
    Threads will not be locked, so posts may still be edited by their authors.
    Just start a new thread on the topic to post if you get an error message when trying to reply to a thread.


New Around Here
I really think this is a century link issue somewhere upstream.

I'm getting 1ms pings from century link with no jitter but stuck at 94.6 Mbps down and 93.9 Mbps up.

I'm running 384.17 Merlin on a my asus 5300. QOS is DISABLED, All ports on the router are negotiating at full duplex 1 Gbps speeds. Hardware acceleration is - Enabled (CTF + FA) CPU is at 3 percent on the router and when I run a speed test the CPU spikes at 20 percent telling me that it's not getting the full bandwidth.

Jumbo frame enabled, NAT is auto with CTF and FA accelerator enabled
Spanning tree is enabled.

Vlan is set for 201, PPOE credentials are all good.

I have rebooted the router and the ONT multiple times. I was getting good speed tests last month and now all of a sudden (nothing changed on my end) it's 100mbps hell.

Any suggestions?


Part of the Furniture
Did you power down the modem/ONT and the router for 15 to 20 minutes or more (an hour + is ideal)?

Then, turn on the modem/ONT, wait 5 minutes. Turn on the router and wait at least 10 minutes after it has booted up to do any testing with it.

What device are you using to do the testing with (I'm assuming a wired client)? Did you try different speed test sites? Did you try different browsers? Did you try testing with a different computer?

Microsoft update day was today or yesterday for you. That may have changed things.

Edit: I just saw you have Jumbo Frames enabled. Turn it off unless all your devices are capable of the same Jumbo Frame specs as the router (not same or above; identical).

When you updated to 384.17_0 release final, was a full reset (specifically, an M&M Config, please see the link in my signature below for further details) performed?

Are you running any scripts via amtm or otherwise?

Do you have any USB drives plugged into the router at all?

calvin tran

Occasional Visitor
Try to reboot your modem. I noticed something wrong about my internet for the last two days. This morning I decided to test the speed, and it was 20-40Mbps/110Mbps with wired or wireless. So I rebooted the router, backed out the changes: parental controls, DNS filtering... and those didn't help. I was about to reset my router but then I rebooted the modem and everything is good again.


Regular Contributor
This happened to me, or something similar. 420/35 line that would randomly drop to 100/35.

Router reboot fixed this. Flashed back to stock for now.


New Around Here
I got it fixed but am unsure what exactly fixed it. A router reboot is always my first line of defense.

I powered down both the router and ONT for over 20 min as suggested. I actually left it all off overnight. The next day in the morning, I turned on the ONT, waited five minutes, then did a hard reset of the router with 384.17 on it. I reset everything up and was still only getting 100/100 with everything negotiating at 1 Gbps, hardware acceleration was enabled. Jumbo frame disabled.

The way my network topology is set up currently is I have the four lan outputs, going into it's own switch on the other end that feeds the rest of my hard wired home. (every room is hardwired with one wire, some with two). These are just throw down net gear dumb switches. So each router lan output is a trunk to each switch where the rest of the network is distributed to the end devices.

8:25 Approx, I ran another speed test after rebooting all of the switches and was still getting 100/100. I was at the point where I was going to take my laptop directly into the router instead of testing through a switch to make sure it wasn't an issue with the switch. They all were negotiating at 1 Gbps as well. Right at 830 in the morning, during the middle of my troubleshooting, I ran a 4th speed test through 5.0 Ghz wifi while walking upstairs to where the router is located. 384/250, and bam faster than 100/100. I went back down stairs to both PC's that I was running speed test on and suddenly I was getting 940/150 where literally 2 min before I was getting 100/100. An hour later my upload increased 960/300. This morning I'm now getting full speeds 908/932.

I'm suspecting maybe someone at Century Link was looking at the ticket I had them create the night before and kicked something in their network coincidentally. All seems to be back to normal now, and I need to reset up IPV6 but all is good. CL was insistent that it was with my equipment, but the CSR's couldn't understand that if it was upstream of the ONT the ONT will negotiate all day long at gigabit but you still will go 100/100 at the upstream equipment effectively slowing me down. What's also weird about it is my download immediately came back, but my upload took some time to get back to normal.

I'm also curious if CL throttled me. They say they dont, but I run quite a bit of video on my network. I have 4 nest cameras uploading full HD video, and we stream quite a bit of YouTube, and UHD Netflix, ect. The CSR made a comment that I had already used 500 gig of data for the month. My response was yea I know that's normal. I would be curious to see what our average monthly usage is. I would not be surprised if it was 2-3 Tb a month.

Latest threads

Sign Up For SNBForums Daily Digest

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