I have been trying to find out why IE uses up so much processing power, but unfortunately all I have been able to find is various ways to fix it.

My problem was caused by leaving the IE open on our server, after checking out network speeds (visited speedtest.net), and after a couple of days, it started to severely slow down our entire network. Checking the performance of the server showed that IE was chewing up a huge chunk of CPU. (99% in the processes tab, and the CPU Usage in the performance tab was at 100%).

The only add-ons that IE had installed, and running was

  • Java (32-bit and 64-bit)
  • Shockwave Flash Object (32-bit)
  • XML DOM Document (32-bit and 64-bit)

Using IE 11, and the only tab open was on http://beta.speedtest.net, and was left open for 2 days (48 hours).

As soon as I attempted to close it, it crashed (not responding), and when I force-stopped the program, the CPU dropped back down to a much lower usage (~20%).

Can anyone tell me why this happened? In my mind, it seems like there was a recurring process chewing up resources, but I would like to confirm this.

  • Why have you said in your title CPU/RAM. Whereas in the body of your question you mention only a figure related to CPU? If you really mean both then you should give the figure for each of them - both of them, and not just one of them. And if you don't mean RAM then don't say RAM. And you should contrast it with another e.g. say what % CPU and % RAM chrome uses(as well as IE the browser you're having the issue with). – barlop Feb 16 '17 at 0:28
  • Also it looks like you have only tested one single website , or at least that's all you mention. And clearly it was a situation where IE had crashed. And -1 It's not fair to accuse IE of using massive amounts of CPU, (as if it uses more than other browsers), when you're actually describing a very specific case where it had crashed. And you've only tested this on one computer "your server". It may use a lot of CPU if it hit some bug. A better question is why is it struggling with that page. Much of your question including title, is worded like you're making some general statement about IE 11 – barlop Feb 16 '17 at 0:31
  • A better title than "Why does IE use up so much CPU/RAM?" would be "Why is IE using up so much CPU/RAM". Or if you only meant CPU not RAM, then say "Why is IE using up so much CPU" And if you only meant it for that particular page that is crashing then say "Why is IE 11 struggling to load this page". – barlop Feb 16 '17 at 0:37
  • @barlop, the page loaded fine, however the issue is that after leaving it open, uninterrupted for 48 hrs, IE was using up an extremely high amount of CPU. I have edited the title. – Ben Feb 16 '17 at 0:39
  • It is loading fine in the sense of getting as far as showing the page, and letting you interact with the page, but isn't opening the page fine if it's using 100% CPU and not closing easily, it has to some extent (as you note- crashed) having opened the page. Note, i've removed the -1 since you edited the title. – barlop Feb 16 '17 at 0:40

To diag the CPU usage issues, you should use Event Tracing for Windows (ETW) to capture CPU Sampling data / Profile.

To capture the data, install the Windows Performance Toolkit, which is part of the Windows SDK (the Windows 10 version works also on Windows 8.x/2012(R2).

enter image description here

Now run WPRUI.exe, select First Level, under Resource select CPU usage and click on start.

enter image description here

Now capture 1 minute of the CPU usage. After 1 minute click on Save.

Now analyze the generated ETL file with the Windows Performance Analyzer by drag & drop the CPU Usage (sampled) graph to the analysis pane and order the columns like you see in the picture:

enter image description here

Inside WPA, load the debug symbols and expand Stack of the iexplore.exe process that has the CPU usage (look at the Weight % Sum value with largest value).

In this view, WPA breaks the usage into different parts (HTML, layout, network). Extand the entry with the largest CPU usage. HEre it is HTML/JavaScript:

enter image description here

enter image description here


Registry settings to push IE CPU Lower

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\iexplore.exe\PerfOptions]


1 Idle
2 Normal
3 High
5 Below Normal
6 Above Normal


0 Very Low
1 Low
2 Normal

Registry Screen Shot

  • 1
    Let's assume that I have no idea what the registry is or what the top part of your answer even is... to me, this answer would be useless. You should add information about how to even access the registry editor in the first place, and how that top part of your answer can be used (turned into a .reg file and merged). – Kyle Applin Oct 19 '17 at 13:18

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