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Captain of the Internets.

Web speed is slow but Torrent speed is fast – Solution!

HTTP / Web speed is slow but Torrent speed is fine on Windows Vista / 7

One morning you wake up to discover that your internet connection speed has fallen by 1/4 its original speed on your Windows machine. Websites are slow, YouTube is slow, all video sites are slow, everything is slow in general now. You begin to suspect it's a conspiracy by your ISP, or maybe your computer is infected with a super stealth virus, or maybe it is the goddamn antivirus which is sucking up your speed!

But then you notice something: the torrent download speed is still as good as it was before. The speed problem did not affect torrent and some other protocols, it is just the Web!

You are in luck! I will show you how to get your net speed back to where it was before or where it should be. It's all got to do with your system's  MTU setting.

First, open a command prompt with administrative powers: Windows > Search > 'cmd' > rightClick > Run as Administrator.

At the command prompt check the current MTU settings and retrieve other relevant information. Type the following at the command prompt:

> netsh interface ipv4 show subinterfaces

You should get something which looks like:

   MTU  MediaSenseState   Bytes In  Bytes Out  Interface
------ --------------- --------- --------- -------------
4294967295 1 0 18535911 Loopback
1500 1 6469930 761576 WAN

Make a note of the name of the second network interface. Mine's called "WAN", probably yours might be called "Local Area Connection".

In all probablity, that MTU value of 1500 is not the optimal value for your system. Let's find out what the optimal value is.

> ping www.google.com -f -l 1500

You should get this is response:

Pinging www.l.google.com [74.125.236.50] with 1500 bytes of data:
Reply from 192.168.1.2: Packet needs to be fragmented but DF set.

See that "Packet needs to be fragmented but DF set"? It shows that the MTU value of 1500 is not optimal for your system. Keep reducing the MTU value till you don't see the "Packet needs to be fragmented but DF set" message anymore:

> ping www.google.com -f -l 1465
Pinging www.l.google.com [74.125.236.50] with 1400 bytes of data:
Reply from 74.125.236.50: bytes=1400 time=138ms TTL=53

An MTU value of 1465 worked for me. Likewise, you find the perfect MTU value for your system. Don't get it too low, else you will end up slowing down your internet connection speed.

Once you get the perfect MTU value, it is time to set it on your system. Do it this way:

> netsh interface ipv4 set subinterface "WAN" mtu=1465 store=persistent

Don't blindly copy-paste that! The interface of your interest is probably called "Local Area Connection" or something like that, in which case, you do this:

> netsh interface ipv4 set subinterface "Local Area Connection" mtu=1465 store=persistent

Now go to http://www.speedtest.net and confirm your internet speed is back to normal and you are getting what you should be getting normally.

Please note this solution for fixing slow internet connection will work only for the condition: torrent and other protocols show expected speed but everything on the browser is slow.

Now that you have fixed your slow internet connection, enjoy this YouTube video!

Exercise

  1. What is MTU?
  2. Why does high MTU make your internet connection slow?
  3. Why is it not recommended to keep your MTU below 1400?
  4. How does low MTU cause slowness of internet connection?
  5. How do you change the MTU on Linux? Mac OS X?

References
  1. MTU

38 Responses to “Web speed is slow but Torrent speed is fast – Solution!”

  1. Ved says:

    I dnt knw who u r n where u r !!! But i will find u and will thank you !!!! 😀
    T_T dis problem was bugging me since last month tried all types of system care software but then ur manual method did the miracle !!!
    Hail d great Spirit

    Thanks a TON !!!!! 😀

  2. Pragy says:

    Holy crap! It worked! sweet :)

  3. Mike says:

    Doesn’t really work. It says “The requested operation requires elevation “

  4. ankur says:

    whenever i set the desired mtu then after that pinging with that mtu got the same result on df fragmented

  5. What! says:

    If i use WiFi do i change the MTU of WiFi instead of Local Area Connection??

  6. ozair says:

    could you please explain it in simple language?? cannot figure out this cmd thing

  7. Dominic says:

    @mike Run command prompt as administrator that will fix it for you

    it made a slight improvement. Thanks

  8. ryan says:

    This actually did help! It worked with hotel wifi, took me a while to work out “Wi-Fi” should replace “Local Area Connection” or “WAN” but after that it was happy sailing. put MTU about 1435 but that was too low, 1450 seems to be the sweet spot but dunno how much that’s gonna affect P2P (for some reason one won’t work if the other is open, e.g. i have to close my browser for torrents to speed up and vice versa. at least with cheap crap hotel wifi)

    ps the best way to know which label to choose like “Wi-Fi” or “WAN” or “Local Area Connection” or whatever is probably to check which one has the most incoming/outgoing kbps. i’m no expert so I could be wrong but that’s what helped me.

    pps actually on second thought I’m not sure that it helped that much. browsing doesn’t really seem any faster and torrents definitely don’t download at the same time as browsing. could just be my crappy pc though.
    pages wouldn’t even load at 1450, however when i changed mtu back to 1500 everything returned to normal operation immediately. could have been coincidence but just commenting for others to consider with their own issues

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