Add-ons, Measuring Performance

After our recent posts on add-ons performance and installation experiences, we’ve seen some questions from developers. This post answers a few of the more common questions, and offers suggestions about what developers can do to improve the add-on experience.

In this post, we described what IE measures (e.g. the impact of each add-on on page navigation) and when IE measures it. One question is how frequently does IE measure, and how does IE calculate the average. There are many alternatives to choose from in calculating an average time, like a weighted average, or geometric average. IE calculates the arithmetic mean of the last 10 recorded data points. (Load and navigate times are stored and averaged separately from each other, and for each add-on.) This process begins with the first time IE runs any add-on. Each time the add-on runs within IE, IE updates the data and recalculates the average. In IE8, this average is the load time number you see in the Manage Add-ons dialog.

Another common question is how the CPU speed of an individual’s PC impacts the load times of add-ons, and the relationship to the threshold used to inform the consumer about the performance impact of their add-ons. On a slower CPU, add-ons that perform more calculations take more time to load. While the overall speed of a PC may impact performance, consumer tolerance and the thresholds of human perception are constant (Einstein not withstanding). The thresholds IE uses are the same regardless of CPU speed.

Directly related to these questions is “what can an add-on do to reduce the amount of time it takes to load the first time it runs?” Developers have many options here. Some add-ons choose to perform one-time calculations, data caching, and other operations the first time they run. One alternative is to do these operations as part of add-on installation. In earlier blog posts we suggested ways developers can make their add-ons run fast, and tools to use to understand browser performance.

We value the feedback and conversations with developers who want to make their add-ons work well so our mutual customers have a great browsing experience.

Herman Ng

Comments (33)
  1. Ubuntu Fan! says:

    hello will Internet explorer 9 be able for us Ubuntu users to use? cause i love Ubuntu but i like internet explorer 🙁 i had ie before i removed windows xp

  2. mmm Nope... says:

    ^^ u will not be able to use IE9 on ubuntu because it is not open source software like firefox or chrome web browser. Secondly why u need IE9 on ubuntu? And also IE9 need Direct2D api of windows not linux. As ubuntu have direct rendering enabled thru display drivers u dont need IE for linux ine then next 1000 years.

  3. Randall says:

    I'm looking at the phrase "threshold used to inform the consumer about the performance impact of their add-ons."  Does that mean users get a notification if their add-ons take too long to load?  (If so, that's WONDERFUL.)

  4. clara vargas says:

    When I first read this web article discussing the Facebook audience claim that's off by 17,000 times I concluded IE Blog's audience should view this:…/Lies-Damned-Lies-Statistics-ComScores-Facebook-Audience-Claims-Are-Wrong-By-A-Factor-Of-17-000 According to ComScore, the average Facebook user is online half a second per day! Yeah, sure!

  5. Miguel Web Developer says:

    This could sound foolish. Or maybe not…

    Why not using hardware acceleration to improve add-ons. You can!!!

  6. Aethec says:

    @Miguel: I don't see how…unless add-ons used calculations that could be rewritten to use DirectCompute…

  7. Nathan says:

    My number one complain about IE these days is one of polish. People like their browser to be fast. Instant-on (or close to it) wins. That's one of the advantages Chrome has; it is exceptionally fast to load. IE is reasonably fast to load but it does the most annoying thing for every new tab. Even though it is opening "about:blank", it displays "Connecting…" for a short period of time before it hands control of the tab's contents to the user. Why does it need to connect to ANYTHING to load nothing? If you must load stuff, load it in the background and keep that fact invisible to me. I shouldn't need to know or care if IE has to connect or load something for any individual tab. Creating a new tab should be instant and should not make me wait for anything if I haven't set a default home page. Neither Chrome, Firefox, Safari or Opera make you wait after you create a new tab. Just saying.

  8. Literacy says:

    "Just saying" that you don't read? That topic has been discussed to death on this blog for the last 5 years.

  9. Internet Explorer 6 FAN says:

    Hello Internet Explorer is dieing look at firefox they listen to what the users want to see in their webbrowsers.  well wanna know what i would love to see in internet explorer 9 is Themes! you know a picture or something to go under to URL bar that would be so awesome!

    Please Replied Thanks!

  10. ieuser says:

    Agree with Nathan, I dont know why MS doesnt handle it well despite being many complains from the users.

  11. Clue says:

    Agree with literacy, it has nothing to do with Microosft and everything to do with poorly-written add-ons. Hence, the topic of this blog post.

    Is it too much to hope that people read before commenting?  Prolly.

  12. Nathan says:

    @Clue – "Poorly written addons"? I've had this problem with every default install of IE8 I've ever encountered. What add-ons accompany the default install?

  13. Clue says:

    All of the random junk you already had on your system. If you didn't know that, it's obvious where the problem is.

  14. Nathan says:

    @Clue – You're a very sour character aren't you? it's easy to put me down when you make sweeping incorrect assumptions. I keep a very clean system (I hate junk, clutter and stuff I don't need), but this has occurred on every fresh install of Windows I've had, on more than one computer and on different internet connections. I do know how to use a computer, I've been coding for over 15 years and using them for a lot longer than that.

  15. Klimax says:

    Nathan: Addons,large zones,slow or poor connection and large homepage(lots of js),CPU hogs outside of browser,not enough RAM,damagade or broken installation of Windows/IE,broken/missing files in user directory,malware,old/buggy drivers,…

    There is way too many things that can go wrong.

  16. Nathan says:

    @Klimax – yes, all of those things can make the problem worse. But the problem is there on clean fresh installs of Windows 7 on late-model PCs with good internet connections and "about:blank" for the home page. At the risk of stating the obvious, Firefox and Chrome both have to deal with all of the issues you mentioned too, yet they can somehow open a new blank tab without forcing the user to wait while they connect to nothing.

  17. Klimax says:

    Nathan 10:08: What specs were those PCs? (strangly I do as well ; and yet both of us have different experience)

  18. Klimax says:

    Nathan (10:14): I know. Yet I got only three times there – once with few buggy addons,second with large RZ and third time cause unkown (and never found what solved it).

    The third case was worst, tab loading time was about one to two minutes.

    Maybe you could try process monitor or some performance monitoring to see WTF is going on.

  19. Michael says:

    Will Internet Explorer 9 have Themes like to have a picture around the address bar.?

    I hope Internet explorer 9 will be faster than google chrome and firefox.

    Please Reply to this post Thanks

  20. Explanation says:

    Nathan, Firefox and Chrome don't have to "deal with" add-ons in the same way, because they initialize their add-ons differently. Further, it's hard to "accidentally" get new add-ons in those browsers, and most antivirus suites don't bother hacking/thunking the heck out of those browsers like they do IE.

    Of course all of this has been discussed to death here for years, and recreating this discussion over and over again isn't very useful.

    Some tips over there:…/ie8-performance-and-speed-tips.aspx

  21. Nathan says:

    @Klimax – I don't remember the PC specs; too many and too varied to list in any case. Suffice to say I've seen plenty of IE8 installations and all of them have had at least a 0.5-2 second wait on new tabs at best. I would suggest it's Microsoft's job to do some process monitoring on the issue, not mine. I'm not begrudging them the need to load resources for a tab, just that a more polished experience would be to hide this load time from the user, irrespective of what hardware and software is present and let it happen behind the scenes while I'm typing in the address I want to visit.

  22. You are broken says:

    if you take more than 1/2 second to launch a tab, ever, your computer is in a bad state. Run without add-ons explicitly using the -extoff command line. Check your AV. Ensure you didn't install SpyBot or anything else that junks up your registry.

  23. Drake says:

    @Ubuntu Fan

    Clearly just here to adverise Ubuntu Linux — which already comes with Mozilla Firefox installed, or you can download Chrome or Opera from the repository.  Why do you need Internet Explorer so badly?  You clearly uninstalled XP for a reason too, so if you're having second thoughts either re-install it or just download Oracle VM VirtualBox and run XP inside your Ubuntu Linux.

    @mmm Nope…

    The hardware acceleration *could* be done via OpenGL on Linux, just to make the point.  Still, never going to happen.

    @clara vargas

    I have to say "troll" but I fail to see what a research companies mis-statistic on Facebook users has to do with IE?  Have Microsoft previously used the data to backup/make a claim that I've missed?

    @Miguel Web Developer

    Some add-ons (mostly toolbars, like Google, AVG, Norton, McAfee) take time during loading because they contact servers to share or download data.  No amount of hardware acceleration will speed up your Internet connection or their servers!


    Under Tools > Internet Options > Connections tab > [LAN Settings] button do you have "Automatically detect settings" ticked?  If so, some seconds may occasionally be lost as Windows tries to determine if there are any settings for your network it has to use (mostly relevant for corporate networks).  Also, if this are corporate PCs you're setting up have you any Group Policies that may cause a slowdown by performing certain checks on the browser?

    @Internet Explorer 6 FAN / Internet Explorer 9 fan forever

    Hello clearly-the-same-person!  Themes support is not critical compared to standards improvements then some badly needed overhauls of the options dialogs and the introduction of other features like a download manager.


    As above: not a desperate feature compared with other features in need to updating.  Also, is IE alone in being the only browser without themes?  Does Safari support them?  (I know Firefox, Chrome and Opera do.)  As for fastest I'm sure this can be achieved with good programming from the IE Team. 😉

  24. I ♥ Areo Glass says:

    hello will the Address bar and all the button and everything in internet explorer 9 be in areo glass on windows 7.  and i love the idea of a faster and better internet explorer but will the back and forward button look the same as they were in Internet explorer 8.0?

    and @Ubuntu Fan EW! What is Ubuntu?

    Btw i love windows 7. Can't wait till 2012 for Windows 8! 🙂 ♥ ☺

  25. @You are broken says:

    I have also witness the same problem, I had a fresh Win7 installed (core 2 duo, 3GB DDR 3 RAM) with no addons, no AV. When I opened IE 8 (no addons, not even flash, SL) it took 1/2 sec to open a tab with a connecting.. label. If you compare this with chrome, you can clearly see the difference. Chrome tab opens with liquid animation without any delay, without any connecting label, without any mouse wait icon. You click new tab icon and start typing the URL. This makes chrome very light and fast. And this is a major concern where MS need to work and make IE 9 competitive against other browsers.

  26. Fastest Webbrowser 1.0 says:

    Hello i have made a webbrowser that does the same as Internet Explorer and firefox and google chrome and opera would do if they were put all together but just different coding and it loads every webpage under 1 second and it has a Built in Antivirus.

  27. Ubuntu Fan says:

    @Drake  i uninstalled windows xp cause it kept on getting a virus on it and it was so slow and ubuntu is faster than what i heard about windows 7 ubuntu loads very Fast 😛

  28. @You are broken says:

    IE 8 tab DOES take time to open with a connecting label.. MS need to work here as well to make the browser open and work fast, if any addon is making the IE experience slow, they show disable them automatically with a user message. BUT ULTIMATELY WE NEED A FAST IE EXPERIENCE. MS are you listening??

  29. Online safety says:

    will Internet Explorer 9 Protect us from Websites that may harm our computers? if not i will continue to always use Internet Explorer 8.

    And Microsoft Should Come out with 1 more Service pack for windows xp.

    And is all the rumors about Windows 8 true that it won't have a taskbar it will be different than windows xp, windows 2000, windows vista/2007, Windows 7/ Windows 2009.????

  30. EricLaw [MSFT] says:

    @Online safety: IE9 will continue to support (and improve upon) the award-winning SmartScreen Filter introduced in IE8.

    Service Pack 3 was the last-ever service pack for Windows XP.

  31. Klimax says:

    @"@You are broken": Did you try to dig in to see what went wrong?

    I am curious what happened to all those people who have such troubles when I don't. (Of course if they forgot about spybot-type protection then it is no wonder as AFAIK Spybot puts huge amount of sites in RZ) Or will I never see an attempt to investigate? (I did those times IE was slow,so why not others. Or did they changed into haters who claim that IE sucks and is slow,when their own anecdote lacks a lot of info.)

    @Nathan: MS cannot monitor what is going wrong on your end,it is not their duty – they did loads of test and apparently didn't see any problem. (with few optional exceptions) So you should take a look,nobody else has direct access to your PC.

  32. Drake says:

    @Ubuntu Fan

    If you keep getting a virus I'd suggest it's probably some software you have aquired from the Internet in the past and so get infected when you install it during the Windows re-install.  Anyway, if you're happy with Ubuntu I still can't see why you would want Internet Explorer on Ubuntu Linux so badly.  Just download an IE-style theme for Firefox and be done. 😉  Alternatively, you could try using Wine to see if you can get IE to run on Linux — though I'm not sure IE7 and IE8 work properly.

    @Online Safety

    As answered by EricLaw, yes: why would Microsoft remove a feature between versions?  That wouldn't make any good marketing or PR sense — "download IE9 today and be less safe" — now would it? :p

    @EricLaw [MSFT]

    So no chance of an Update Rollup 1 for Windows XP then?  It would be good if Microsoft did one of these say once a year to prevent having to slipstream/keep separate so many post-SP3 updates.  There should have been a final rollup for Windows 2000 too!

  33. imnotrich says:

    Website developers and graphic designers often run many different browsers on their computers, so they can see how their creations render under different browsers. Remember there have always been two sets of web standards. The official standards, and the standards recognized by Internet Explorer. So a page written to the "standard" will not always render in IE, and web pages written for IE won't always work with alternative browsers. Think I'm wrong? Google "user agent switcher" for Firefox. An actual add-on that allows your browser to lie about it's identity! These days Chrome is the fastest browser on the planet, there is a PC, MAC and Linux version although Chrome DOES have some privacy issues which are not easily resolved I still highly recommend Chrome. Unless you're a programmer or web designer there's no need to run IE on Linux.

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