Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

i have certain pages where ie (even 7 or 8) seems to take a long time to render. What is the best way, tool to find out what is the bottleneck in ie (as firefox and chrome seem quick)

share|improve this question

migrated from Dec 29 '09 at 23:51

This question came from our site for professional and enthusiast programmers.

IE... is very slow. Not really much of a way round it :( – Phoshi Dec 29 '09 at 23:54

Unfortunately since IE has a notoriously slow javascript engine (yes, even 7 and 8 :/) you're probably going to find that the only way to noticeably improve performance is to heavily limit DOM manipulation. That, in my experience and according to most of the benchmarks out there, is the slowest part. Are you doing a lot of element selecting and modifying in a load handler (as in, as soon as the DOM has loaded)?

Also, are you using a library? Not all are created equal :) Give jQuery a try if you aren't using it already.

share|improve this answer
i am heavily using jquery – leora Dec 29 '09 at 13:17
jquery will hit both the big performance holes in all versions of IE (IE7 and 8 improved things a little, but only a little). Both the JavaScript engines and the page rendering engines are inefficient compared to those found in most other modern browsers and heavy use of jquery can tax both. There are some optimisations you can make (which boil down to doing as little as possible) but the jquery library probably already tries to do most of them for you. MS promise that IE9 will improve both JS running and page rendering performance - by how much is yet to be seen. – David Spillett Dec 30 '09 at 0:30

There may be several reasons for IE to not to perform well. Generally, heavy websites having rich multimedia content tend to slow down the browser. To improve performance in this case, you can try to resize the cache to say 128MB or something. (Start Internet Explorer, Select Tools -> Internet Options -> General. Under Temporary Internet Files click the Settings button and type the amount of disk space to use.)

But, I would recommend you to use Mozilla Firefox or Google Chrome as alternatives to IE.

share|improve this answer
i dont control the browser. . .thats the users – leora Dec 29 '09 at 14:37

Yahoo! provide a service called YSlow that does analysis of page speed.

share|improve this answer

You could identify where is the bottleneck in IE by using an HTTP proxy such as Fiddler: this would help you to find if a long time is spent in downloading files, in rendering stylesheets or running Javascript, by looking at the intervals between downloads.

In my experience, if Javascript is the bottleneck, you can optimize your code in Firefox, using the profiler part of Firebug to identify long-running code. Most optimizations will not be specific to Firefox and will benefit other browsers, including Internet Explorer as well.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.