Speed up Microsoft Edge with TCP Fast Open

Martin Brinkmann
Jul 14, 2016
Updated • Jul 5, 2017
Internet Explorer, Microsoft Edge

TCP Fast Open is a new feature of Microsoft Edge that speeds up the web browser's page loading time by over 10% on average, and in some cases up to 40%.

The feature is currently only available in preview versions of Microsoft Edge available on Fast and Slow Ring Insider Builds.

It seems likely however that Microsoft will make available the feature in next month's Anniversary Update for Windows 10.

Before we take a look at how TCP Fast Open is activated in Microsoft Edge -- it is not enabled by default -- it is useful to find out what it is and how it manages to speed up the page loading time.

Speed up Microsoft Edge with TCP Fast Open

tcp fast open

TCP Fast Open is an extension of the TCP protocol that enables data exchange during TCP's initial handshake.

The whole process is highly technical; it uses a cryptographic cookie that is stored on the client during the initial connection to the server which is used later on for authentication to start data transfers early.

Sending a cookie needs to be supported by the server for TCP Fast Open to have any effect. If that is not the case, the server ignores the request and a regular connection is established instead.

In short, the client and web server needs to support TCP Fast Open for you to notice page loading differences. It is likely that web server compatibility will improve in the near future as both Microsoft and Apple support the feature now (Google on Linux and Android).

If you are interested in the full details check out Google's publication on TCP Fast Open, the Wikipedia article for an overview and links, or Bradley Falzon's overview which is a bit easier to understand.

Enable TCP Fast Open in Microsoft Edge

As mentioned earlier, the feature is only available in Microsoft EdgeHTML 14.14361 and higher. The browser version is only available when you run Insider Builds of Windows 10 currently.

Click on the three dots in the Edge interface, select Settings, and scroll all the way down to display the version of the browser.

To enable the feature and speed up Microsoft Edge, do the following:

  1. Type about:flags in the browser's address bar.
  2. This opens experimental features.
  3. Scroll down until you find the networking section.
  4. Check the "Enable TCP Fast Open" preference to enable it.
  5. Restart Microsoft Edge.

Depending on how you use Microsoft Edge, you may notice a speed increase when connecting to certain web pages using the browser, or no benefit at all.

Since web servers need to support TCP Fast Open for Edge to benefit from it, you will run into situations where you won't notice a difference to before.

Speed up Microsoft Edge with TCP Fast Open
Article Name
Speed up Microsoft Edge with TCP Fast Open
TCP Fast Open is a new feature of Microsoft Edge that speeds up the web browser's page loading time by over 10% on average, and in some cases up to 40%.
Ghacks Technology News

Previous Post: «
Next Post: «


  1. John said on July 22, 2018 at 10:57 pm

    Appears that in Edge 17 with Spring release this option has disappeared in Flags? Don’t know if its now on my default or has been dropped entirely?

  2. Suresh Bhatt said on December 1, 2017 at 9:23 am

    Thank you so much for this article.
    I was downloading a movie with WiFi but speed was really slow, but when I enabled this setting- Download speed raised by *5 times

  3. jupe said on July 19, 2017 at 7:56 am

    After reading this article I had a look in about:config in Firefox and found “network.tcp.tcp_fastopen_enable” ? Does that mean that Firefox supports it too? How can I test to see if it works? Would anything come up in the browser console or something?

  4. Techblogger said on July 20, 2016 at 12:01 am

    The problem I see with changing Edge in this way is the adblock filter no longer work. So I switched it back

  5. Jacob said on July 16, 2016 at 12:59 pm

    Let’s push other browser vendors to implement this one as well.

  6. Sais said on July 15, 2016 at 9:38 am

    Seems like Edge is going to get my attention more after the anniversary edition is released.

Leave a Reply

Check the box to consent to your data being stored in line with the guidelines set out in our privacy policy

We love comments and welcome thoughtful and civilized discussion. Rudeness and personal attacks will not be tolerated. Please stay on-topic.
Please note that your comment may not appear immediately after you post it.