Why is IE using up so much CPU?

Question

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.

Solution

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).

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

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:

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:

Comments

[Sonickyle27]

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).