IE8 slow? Maybe this tweak will help

Update 28-March: As I said in the original intro to this post, I was reluctant to publish this tweak, because I have absolutely no explanation for why it should work. If someone else had posted this, I would have assumed it was snake oil and would have been extremely skeptical. As skeptical as Rafael Rivera, even.

Actxprxy.dll is one of the core libraries for Internet Explorer (along with a few others such as Urlmon.dll and Mshtml.dll). If it’s not properly registered, IE won’t work at all. And re-registering it should never be necessary except in extreme circumstances.

Having said all that, I can only point to the experience I reported in the post linked below, which has since been confirmed by others in comments and e-mails. Are they all experiencing placebo effects? That’s possible, I guess. It’s also possible that some third-party software or add-on is somehow screwing up this DLL and its associated registry settings. I have contacted some engineers at Microsoft to see if they can shed light on the issue and will follow-up after I hear from them.


Over at ZDNet I just published the results of some performance testing I did involving the current crop of browsers. During the course of my research, I stumbled across a tweak that I was at first hesitant to publish. After thinking carefully about it, I decided to do so. I’m glad I did. I have now heard from easily a dozen people via e-mail and in comments who say the improvement in performance for them is amazing.

Please read the original post (Is IE8 really fat and slow?) to get the full background. If you’re experiencing problems with IE8 being slow to load pages, especially when multiple tabs are involved, this might be worth a try. Because this tweak is simply registering a DLL that should have been registered as part of the IE8 installation, there is no harm that can come from trying this.

Here are the instructions.


1. Click Start, then click Run.

2. In the Run dialog box, type cmd and press Enter.


3. In the Command Prompt window, enter this text and press Enter:

regsvr32 actxprxy.dll

4. Restart your computer.


1. Type cmd in the Start menu Search box.

2. Right-click the Cmd shortcut that appears at the top of the search results list, Under Programs, as shown here.


3. Choose Run As Administrator.

4. In the Command Prompt window, enter this text and press Enter:

regsvr32 actxprxy.dll

5. Restart your computer.

If this works for you, let me know in the comments below…

82 thoughts on “IE8 slow? Maybe this tweak will help

  1. Thanks Ed!!! What a significant improvement this made to IE8 on my PC (IE8 on Windows 7 PC). I really thought IE8 was fat and slow until I tried this. Can not believe that Microsoft has not done something to let the masses know about this. I am going to use IE8 this weekeknd to see how it performs. Will try watching some March Madness games using IE8. Again, thanks for a great tip and if you have any other tips, please share them!!!

  2. Does this also work on Vista 64bit? I ask because of the “32” at the end of “regsvr”.

  3. You should do a Mark Russinovich-style post, to explain how you discovered this problem. The cause would be interesting indeed. I suspect either a race condition, or an antivirus/antispyware program.

    Setup tends to be one of the biggest hurdles in using a program. Windows 7 will be the best way to get IE8.

  4. Well done ! Yes, it worked very nicely. Actually made a world of difference in page loading time, meaning it reduced it “big time”. I presume this cmd has to be run only once unless IE8 has to be reinstalled?

    Is this tweak applicable to IE7 or only IE8 ?

    Similar question to “Michael’s” with a twist, does it apply to the 64bit version of IE7 and/or IE8 ?

    1. This tweak does indeed work on x64 Vista (and Windows 7). I’ve successfully run it here. It’s worth noting that in x64 Windows versions the default browser is actually the 32-bit version. Although there’s a 64-bit IE, it’s not used by default, primarily because add-ons like Flash and Silverligbht are unsupported.

  5. Thanks Ed,
    I tried this on both Vista and Windows 7 and it improved performance on both significantly.

  6. You wrote: “I was at first hesitant to publish.”

    Why? Is there a potential downside to entering this command? Could it cause other unintended problems with the system? Is this something only people who notice slowness should enter, or can everyone do it without worrying about side-effects?

    1. Nancy, there’s no real downside to this. The DLL in question should be registered on any Windows system. If it’s registered correctly, re-registering it has no deleterious effect.

      So why was I hesitant? I like to have a solid understanding of why a particular procedure works before I publish something, and I still have unanswered questions about this tweak. I know from experience that once something like this gets published, it becomes like an urban legend. But given the response I’ve had so far, I’m happy I did this.

      When I hear more from Microsoft, I will update the post to add the why along with the how.

  7. Ed,
    I sent a personal email indicating that it’s made a difference for me too, but perhaps I spoke to soon, though I’m thinking this might be a different issue. When I click a link in Outlook, it goes to IE8, but usually says that ie has stopped working, and then it tries to refresh all of the tabs that are open, sometimes they too stop working, and eventually, sometimes after 2-3 times of clicking the close the program pop up dialog it will finally open up the liked web site. Sometimes it nevers open. It seems with an earlier release candidate that dropping the Live toolbar made a difference. Do you know what might be going on? I’ll try taking off the Live toolbar addin and see if it makes a difference. Thanks

  8. I guess I should have checked before writing. I don’t have Live toolbar enabled. So that’s not the issue.

    1. You can try resetting IE completely using this technique: Open IE, click Tools, Internet Options, Advanced tab. Click Reset button. You will need to reinstall any add-ons or customizations.

      As a less drastic measure, you can also run IE in “clean mode.” Make sure all instances of Iexplore.exe are closed. Then click Start, All Programs, Accessories, System Tools, and click Internet Explorer (No Add-ons).

  9. March 27, 2009 – Thanks a lot Ed, I was thinking about going to IE7, but this fixed problems

  10. It would be interesting if people could post whether or not the DLL was registered on their system before taking this step, but I haven’t found a simple way of determining that.

  11. I have a different problem: If I have a tab open with OWA for Exchange 2003, tab operations are almost impossible. I can’t create or open new tabs without waiting for a very very long time (> 30 seconds, but haven’t timed). However, operations within the OWA tab are normal.

    Bottom line, IE8 is slower than other browsers, and I am not talking about Javascript benchmarks. The application itself is slow.

  12. Major improvement opening pages and multiple tabs on Vista SP1. See similar improvement on XP. Good catch.

  13. I ran the tweak and can definitely tell a difference in the speed at which IE8 loads (I’m running on Vista 32 bit Premium Edition). Pages load noticably faster! I really like IE8 but was not pleased with the slow page loads. Your suggestion really made my day!

  14. Seems to be a nice tweak.

    And thanks for the bonus information about why IE7/8 32-bit is the default on my 64-bit Vista system (although I’ll still use the 64-bit IE8).

  15. I’m tickled with this IE8 speed fix. The speed fixes I have tried in the past for various kinds of software didn’t work as advertised, if at all. This fix though, wow! IE8 is now faster by a factor of 3x for me. That is with only two open tabs, though, so not a scientific test.

    Try to avoid the midday Arizona sun–it will burn your braincells–and keep up the good work, Ed.


  16. Thanks Ed…seems to have made a significan difference on my 3 Vista machines as well as my one XP machine. It seems so much more response that before this tweak.

  17. Ed:
    I followed your script for Vista, except I did not reboot. I really hate doing that. It does not seem to matter. IE8 is now running much faster.

  18. Sorry…ran as Admin (I guess that is what you mean by ‘elevated’)…it worked….now whether it made IE8 faster is another matter…! I don’t see, rather perceive any significant difference…but thanks Ed, for the tip…now I wish you had a tip to make scrolling smoother with IE8…particularly using the Logitech Setpoint software!

  19. I tried using the command as you specified on my 9 yr. old Toshiba Tecra 8200 that runs Windows XP Home Edition SP3. As soon as I hit enter after typing in regsv32 actprxy.dll I got the following error message:

    LoadLibrary(“actprxy.dll”) failed-The specified module could not be done.

    I just this means I will be stuck with a slow IE8.

  20. Ed…apologies if this question is in the wrong place…b ut for n00bs like me, can you perhaps state clearly which of the four mainstream browsers are the safest for everyday browsing? The options are: IE8, FF (latest stable build); Safari (latest stable build) and Opera (9.64, this I know because I use it all the time…till IE8 came out, that is!)…this would be a great help!


  21. I assume registering the DLL is only required once just per system. Not once per user account.

    On the three XP machines I installed to, one has a significant problem. I already rolled back to IE7 once yesterday, and I’m about to do it today. My problem seems different from what you describe: IE8 is extremely slow to launch. IE8 crashes when I try to close it without waiting for the complete launch.

    This is my parent’s computer. It hasn’t had a re-install of XP Pro since I built it in 2005. (It was running IE8 RC1 no problem prior to this upgrade.) I will try the reset and ‘no add-ons’ operations you describe.

    I’ll probably live without IE8 on that computer until it’s delivered via the normal Tuesday upgrade. Thanks for the help!

  22. @ Rick –

    RE: “It would be interesting if people could post whether or not the DLL was registered on their system before taking this step, but I haven’t found a simple way of determining that.”

    I’m very curious about this as well. It would be beneficial to know how many actual cases of the unregistered dll are found before applying the fix..

    For a very simple and free GUI-based way to check to see which dll’s are registered, I recommend using Nir Sofer’s RegDllView tool:

    Just scroll over to the “Name Only” column and sort on that field. Should be easy to pick out the target DLL that way in the list.

    It also can provide the “last registered date” and file date/version information. Also good things to know in advance while troubleshooting this issue.

    That should give everyone the info they need before running the fix.

    It was registered just fine on my XP/Vista systems that had been upgraded to IE8.

    On the other-hand, it might also be reasonable that somehow the registration is present but corrupted. I’ve seen that issue pop up a few times across various troubleshooting posts.

    See MS Help and Support Article ID: 555027 (for XP but should apply to Vista as well)

    In fact according to this KB, it is recommend to first attempt to unregister the following DLL’s before re-registering them.

    “Note: Please try first to register the urlmon.dll and actxprxy.dll and restart Internet Explorer.”


    –Claus V.

  23. Worked great! Now I don’t get the spinning endlessly syndrome and have to shutdown multiple instances of IE. (I have Vista 64)

  24. Follow up to my previous post. I tried a reset of the IE8 settings to no avail. Uninstalling IE8 restored the system to normal speed.

    The new IE slowed user logon an extra 20 seconds in addition to being slow to launch itself. I wonder what the deal is. I suppose I could reinstall IE8 RC1, but I won’t bother. My parents are set up to use Firefox anyway.

    I spent a lot of time messing with this. It wasn’t a total wash, as I took the opportunity to uninstall programs cluttering up their add/remove control panel. I removed Windows Live Essentials, among other things.

  25. I tried the ‘tweak” unfortunately it made no difference. IE8 still very slow and periodically “stops responding” just like IE7 did on vista

  26. Russ, if you were having problems with IE7 crashing before upgrading to IE8, my guess is that you have a conflict with another program or an add-on. I recommend that you try running in no add-ons mode to see if the problem goes away temporarily.

  27. @Claus, thanks for the tip. I should have thought to look on Nirsoft, since that site is a goldmine for tools like this, right up there with Sysinternals.

    Looks like mine was registered on the day I installed Win7, but like you say, there can be faulty registrations, so this yes/no information maybe isn’t that helpful unless some people can show it’s not registered at all.

    Note that the article didn’t mention anything about unregistering first, but I’ve seen that advice before for various DLLs.

  28. Hi Ed! I thing, alon with IE being fat, the biggest problem I find with IE is it requires too much time for new tabs( or windows) to instantiate. So please, if you can help me on this, as it is really very irritating to see a new tab taking 3-4 seconds to load.

    1. Claud, do you have a link for that? I can’t imagine any circumstances under which this is “dangerous.” There are multiple Microsoft Knowledge Base articles that recommend this technique as a way to repair a damaged installation of Internet Explorer, and none of them mention any potential for side effects.

  29. @Arnav: That is also my problem with IE 7 and now sadly IE 8

    Click new tab button, wait for 2 to 10 seconds, new tab opens. while waiting you can’t type the address because you can’t focus the address bar until the tab is open… seems to be a complete and epic fail but it’s been that way since IE7 introduced tabs…. I was hoping IE8 would have this inteface flaw fixed but no such luck.

    In FF3 by comparison, you click new tab or press Ctrl-T and the tab opens instantly and you can type the address while it’s opening.

    so yeah other then the new tab problem, IE 8 seems ok, bit quicker, I like the tab process isolation, but it’s weird how it allocates iexplore.exe processes to tabs, at least with chrome you can see a one to one relationship… but if it works, who cares!

    Will try the tip and report back if new tabs open quicker.

    As others have said, it would be nice to know what actxprxy.dll is/does and why it’s not registered already…

  30. hmm tried registering the dll (this is Windows XP SP3 w/ 2GB)

    no change, tabs still occasionally (one out of every 2 or 3) take a long time to open, and often take a long time to close.

    closing tabs is slower then IE7 and opening tabs is almost the same, perhaps a little slower at times and sometimes a little quicker.

    I then tried registering urlmon.dll as that’s also suggested on the older fixes for IE…
    but it had no effect either.. oh well worth a shot I guess

    1. Ravi, Paul is simply repeating what Rafael wrote in his post and adding his own booming commentary. Paul has done no reseaarch of his own, and for him to be so emphatic about it without doing any testing or further research is laughable.

      Rafael tested this procedure on a system that was properly configured and determined it had no effect. I believe that’s true in that specific case, but he needs to try this on a system that has been upgraded and is performing poorly. For a hypothesis on why that might cause problems, see Mike Dimmick’s comment above.

    1. Claud, I already linked to Rafael’s article in the firwst paragraph of this post. But please tell me where he said this was dangerous? He said no such thing, and for you to imply otherwise is irresponsible. He has his opinion, but I am awaiting further facts.

  31. This DLL implements a COM Proxy/Stub class. Whenever COM has to pass a call to another process or thread, it has to marshal the call – write the arguments, and anything they point to, to a separate buffer that the other thread can read, then interrupt the other thread and tell it to perform the operation. The custom proxy/stub contains code to do this.

    The DLL registers for numerous interfaces that are part of Explorer and IE (this would be one of the few places where IE is ‘part of the operating system’). IE is largely one big COM application, using a lot of COM components in one frame (each tab is a WebBrowser control, largely implemented in shdocvw.dll). Without working proxy/stub code, marshalling some of those calls is going to fail. What effect that has on IE is going to be pretty random. I’m surprised some of the tabs work at all, in that case.

    I suspect that some other piece of software being uninstalled has deleted some of the interface keys, and that’s breaking IE in a way that wasn’t noticed before. One difference is that IE8 now implements tabs in separate processes, unlike IE7 which used different threads; marshalling calls between processes takes longer than between threads. IE8 for Windows XP does not include an updated actxprxy.dll; nor did IE7. It is updated in XP SP3. Because it’s not installed by IE, it’s not re-registered by IE’s installer.

    Unfortunately it’s common for programs to redistribute components they’re not supposed to, or to pick up registrations they’re not supposed to. Installers often reverse-engineer component registrations and then uninstalling that program removes registrations that it created, which it shouldn’t have been creating in the first place, breaking other components.

  32. To summarize, this is not a tweak. A tweak suggests some non-default setting. This is the default setting and registering this DLL will restore that setting if something else has deleted it. If that’s the problem causing IE8 to slow down for you, it will fix it. If not, it won’t. Someone who installs a clean copy of Windows, then installs IE8, will not see the problem and won’t see a speed-up.

  33. This works just great, until the next time you turn on your pc, then IE8 runs like a pig!. Does this speedup procedure have to be done every time I boot my pc?. Seems like it.

  34. I really had hoped this would work, but it did not. My problem is when I click on a button, or another tab, it takes 3-5 seconds for the reaction. I did the procedure exactly how you said and it didn’t help my problem. Does anyone have any suggestions? I tried disabling all add-ons and it doesn’t help either.

  35. This worked great for me. Some pages, such as, toook a long time to load and sometimes pegged my cpu utilization. Now they are fine.


  36. You know why it seems to work? cos you restarted. once the pc has been going for a while, it slowly goes back to slow…

    1. No, Jose, that’s not it. On the systems where I tested this and sawa positive results, I already tried multiple restarts and in fact a variety of other troubleshooting steps.

      I’ve acttually been doing this for a few years, you know. 😉

  37. Thanks Ed.. IE8 was incredibly slow and my CPUs were running at a 100% constantly. I still have slow downs on some web sites but in general CPU use is back to normal and the pages load quite fast. I notitced the biggest difference viewing movie trailers (Apple site) which would not run prior to your fix. I also disabled some of the addons (surf canyon) which were more anoying than useful.
    cheers ….. Dan

  38. Much like the author’s skepticism about posting the “fix” I was similarly skeptical about how in the name of all that is holy it could possibly make a difference in performance as these sorts of things either work or don’t work.

    Now I have probably even less of a clue than him as to why this works and, more importantly, what on earth could have broken the registering of this dll in the first place, but so far it does seem to have worked quite well for me.

    My issue may be slightly different from that of others or it may even be that the issue doesn’t present itself on this computer until it’s remained turned on for a significant amount of time. I’ll have to come back to that in a while after testing over time if it really did permanently fix this or if the fresh reboot is the cause. Anyway, my issue was that opening links in new tabs in IE8 was painfully slow (complete lockup of IE for anywhere from 20-60 seconds before opening new tab and then slowly rendering it) as well as slow startup and also the complete and utter inability to manually open new tabs with the new tab button or the keyboard shortcut Ctrl+T. Attempting to manually open new tabs resulted in a brief flicker on the tab bar indicating an attempted opening of a new tab, but it would immediately disappear (as in within less than 100ms after clicking).

    Ran the command to reregister the dll, rebooted and immediately fired up IE. It now starts normally and there are no problems opening new tabs.

    It should be noted though that since this is a completely fresh reboot I have very few of the normal background apps running so if any of these were conflicting with IE before and causing the issue that may incorrectly lead me to assume the dll register fixed it, so again, I’ll have to report back with an update on this in 24 hours after leaving the computer running with the usual software.

    Ifs and buts and disclaimers and hypotheticals aside, IE does now load perfectly fine for me and though I don’t know WHY it does so it most certainly still works. And since there’s no real risk of causing harm with this tweak/fix there’s not really much reason not to give it a try for anyone else having similar problems.

    Let’s hope MS gets back to you with a detailed explanation on how and why this works and what may be causing the issue in the first place, Ed. I’d be very interested in hearing about it so that I might avoid the problem entirely in the future.

  39. Well, that was a quick 24-hour period. It seem my particular problem was not caused by, and therefore neither fixed by, anything related to actxprxy.dll.

    I use a software KVM solution called Synergy ( that is apparently conflicting in some way. Problem suddenly resurfaced and while shutting down one app at a time to pinpoint the issue, synergy appears to have been the culprit in my situation. Likely just a privilege elevation discrepancy between applications (god that stuff is a nightmare sometimes). Fiddling around with privileges now to sort it out, but that’s a different topic entirely and I won’t bore you with the full details.

    tl;dr: Disregard my previous post as it is apparently unrelated to the topic here.

  40. This tweak made all the difference in the world to me.

    Frankly, I can live just fine without using IE except for seeing how webpages I write look in it… but with my IE8 so horribly slow, I was unable to use a program that I need that relies on it.

  41. regsvr32actxprxy.dll ….regsvr32 actxprxy.dll

    which one correct..with space or with no space?

  42. if i am register regsvr32actxprxy.dll, is it will influence my vista os system or any other browser like firefox?

  43. how can i delete regsvr32actxprxy.dll from my registry?
    when i open new window google alway say not responding at the top of my ie8 browser? what is going on?


  44. There is nothing to delete from your registry. Try using the No Addons mode of Internet Explorer (it’s in Start, All Programs, Accessories). You can reset IE to default settings by clicking Tools, Internet Options. Then click Reset on the Advanced tab.

  45. in accesorries there is no addons mode of internet explorer…how can i get setting no addons internet explorer?

    if i reset from advance tab it means that regsvr32actxprxy.dll will not function anymore?


  46. I have been having an issue with the new ie8 ever since I installed it. I even was considering returning to ie7… this tweak is absolutly the best thing I have ever come across not only did it fix the nonresponsivness of my ie it also made it way faster. I recomend anyone having an issue with ie8 to give this a try.
    Thanks Ed!

  47. It’s like day & night. One minute your sitting all frustrated and the next minute your sitting with this big smile on your face. The difference is amazing.

  48. Will I have to say this did work for me. I was reluctant to believe that this would work, but it did…what a difference!!

  49. I did the tweak, with no improvement. I then deleted all the accelerators except for the one for email (still to be determined if I am going to use or not) and then shut down the suggested sites application. Now it seems to have sped up significantly, except when opening a new tab.

  50. Hi Ed. I am absolutely thrilled , as I have just used your tip about hurrying up my sluggish IE8, and it has worked a treat. Thankyou so much, very much appreciated. Why couldn’t Windows have fixed it ????

  51. Hi Ed,

    I tried your tip and it looked like it was working. After some minutes indeed, the slowdown started again. So I did uninstall the most recent Google Toolbar and reestablished your tip again.

    After a reboot I can say that tabs are opening measurable faster, even though it is still unacceptable to wait for some seconds.

    Interesting is that, if you are opening a tab without an URI, it is opening way faster than with an URI.

    Turning of all plug-ins makes this a bit faster at all, but from a developers standpoint, still there it is questionable why it takes that long at all. Additionally, it would be quite interesting how you figured out your ‘solution’ at all as well as I wonder what the real issue is and why I personally experience a vast difference between IE8/Vista 64bit and IE8/Windows 7 – the latter saves at least min. a second – even though the issue is existing as well.



  52. Hi Ed,

    Unfortunately, I am having to retract my previous comment (76), as the fix didn’t last, but after a lot of work I have managed to uninstall IE8 and to re-install IE7 successfully. I would have loved to have been able to keep IE8, but it was just too slow. I hope it can be fixed by Microsoft.

    Keep up your good work, which is appreciated.

    Kind regards.

  53. Hi Everyone! Just wondering if someone can tell me if there is a space between the 2 and the a or is it all one, for Ex. (regsvr32actxprxy.ddl)

    Thank you all,

    1. It’s two words the regsvr32 command followed by the filename/argument, actxprxy.dll. So there’s a space between the 2 and the a.

  54. Wow Mr. Bott, that’s amazing how quick you answer? Very impressed, keep up the great work!!!

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