Home > Computing, Networking > Linksys WRT1900AC slow internet speed

Linksys WRT1900AC slow internet speed


Here is a strange problem.  Comcast recently doubled my internet speed according to an insert in my bill.  I have performance internet which means I should be getting 25Mbps download speeds.  Doubled I will get 50Mbps!  This is nice.  I follow the instructions to power cycle the modem, then the router and blow off rebooting the PC since I know that is not needed.  A quick speed test and I’m getting a whopping 16Mbps download?

Time to play the fun tech support chat game with Comcast.  We go through the standard stuff of power cycling the modem and router.  He even asks if the modem is connected to a surge suppressor or extension cord (wtf?).  Finally he asks if I can connect directly to the modem and run a speed test.  So I grab a laptop and plug into the modem, but I can’t get an IP address no matter what I do (different cable, release, renew, etc…).  Finally I connect the modem to the router and plug the laptop into the router and run the test.  Everything is right next to each other so it’s essentially the same as plugging into the modem.  Same 16Mbps download speed.  They schedule a tech to come out.

The tech comes out and figures it’s a modem problem since he’s seen plenty of them in this area.  He sees the modem (surfboard 6120) and says it’s probably not the modem.  He checks signal on the cable and that is good.  He then goes and gets a laptop from his van and comes back.  I explain that I tried that and couldn’t get an IP address.  He explains that with that modem you have to power cycle it whenever you change what is plugged into it.  That’s a good bit of info I should have been told earlier.  Anyway, he proceeds to do a speed test with his laptop plugged directly into the modem and gets 60Mbps!  Ok.  He then plugs the modem into the router, power cycles the modem and connects his laptop into the router.  Speed check comes up with 16Mbps.  Bad router he says.  I agree and he is on his way while I find the box and receipt for the $300 router I just bought a few months ago.

Before going through the pain of returning the router I decide to do a quick google search and I find this:  https://community.linksys.com/t5/Wireless-Routers/WRT1900AC-Slowing-down-internet-drastically-Advanced/td-p/878775

I had turned on Media Prioritization for my computer because I kept getting disconnects on a game I was playing and figured it might help.  I turned off Media Prioritization and ran a speed test.  60Mbps download speed!

So at first I figured it was a bug in the firmware.  Then I noticed there was a settings link to the right of the on/off button.  I clicked it and saw an entry labeled Downstream Bandwidth and it was set at 16286 Kbps.  I changed it to 1000000Kbps and turned Media Prioritization back on.  60Mbps download speed!  I find it very odd that by default the router is set to limit downstream bandwidth to 16Mbps once you enable Media Prioritization.  I’m sure someone just came up with a number figuring that would be plenty fast enough.

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  1. Steve
    April 11, 2015 at 5:04 PM

    Thanks for this post. Same thing just happened to me. I owe the tech support guy at Wowway a big apology for the crap I gave him. I refused to bypass my WRT1900AC until he said he couldn’t help me anymore. Plugged the PC directly into the modem and immediately got the speeds I’m paying for. Talk about egg on my face. Big thanks to Linksys for that hidden setting. Sheesh.

  2. April 22, 2015 at 10:41 AM

    Thanks for the post! This helped me as well. I just picked up the WRT1900AC to replace my old DIR-655 and after getting it setup I noticed my internet speed was way too slow. I was only getting ~5.5Mbps on speedtest when I should be getting 25Mbps. When connected to my Huawei modem directly over ethernet I got my 25Mbps so clearly the problem was the new router. I had Media Prioritization turned on and it turns out by default the downstream was limited 6192kbps. What a silly default! I put it up to 2000000kbps(the max) and after saving the config (you have to click ‘Ok’ twice, once on the tab and then again on the Media Prioritization page or your changes will not be saved) I’ve got my full speed back on the router. I really like the WRT1900AC so far but little flaws like this in the stock UI/firmware really detract from the perception of the product. Will have to try out some other firmware when the opportunity arises.

  3. Rokair
    June 15, 2015 at 8:14 PM

    Guys and Gals,
    This setting should by default be auto or require you to manually set it the first time that you turn on QOS (media prioritization). But it is a very important setting if you actually want QOS to work correctly. It should be set to about 90-95% of the actual max bandwidth you can measure when QOS is turned off. You will see that you then get slightly less max bandwidth but then the router can actual manage the priority of you web traffic.

    There should also be a similar setting for upstream.

    Setting these values to something really large me as that you will still have the router cpu overhead of QOS without any of the actual benefits of the same.

  4. marksun
    August 10, 2015 at 1:19 AM

    Chuck you nailed it! Great comments too. Thanks!

  5. Babylon Moshi
    November 28, 2015 at 3:22 AM

    You’re the man, DUDE! Finally fixed my damn problem.. I’m paying for 100Mbps and was getting only 30 on WiFi devices.. After I changed that limit i’m at 96Mbps and that’s in the farthest room from my house. THANKS!!!!!!!!

  6. Jeremy E
    March 25, 2016 at 3:22 PM

    where did you go to make these changes? I have the same problem too. Thank you!

  7. March 29, 2016 at 7:31 PM

    Log into the router, click Media Prioritization and then click it off.

  8. May 8, 2016 at 6:35 PM

    I’m having the same problem. Thanks for the solution. It
    worked!

  9. Steven
    August 3, 2016 at 8:33 PM

    Great answer! I had the same problem in 2 different routers. Fixed both of them. Now they are screaming!

  10. TC
    August 18, 2016 at 8:59 AM

    Outstanding! That was a quick fix and now I’m getting 120MB/s vs. 80MB/s

  11. Dave
    October 29, 2016 at 7:45 PM

    Worked like a champ. I have a Linksys AC1900 and had my Media Prioritization turned on and my Downstream Bandwidth at like 6429. I never knew to change those values. After turning prioritization off and adjusting my DB to1024000, I’m hitting 85Mbps at 50 feet from my Wi-Fi. On the other side of my house I’m only hitting 42Mbps, but I put a range extender there and now I’m hitting 85’s again!! Great fix, thanks for the assist!!

  12. John
    January 23, 2017 at 7:28 PM

    Chuck, where were you before I finally found an answer to this problem. Thanks for what you do to help others

  1. August 10, 2015 at 1:07 AM

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