High CPU usage at idle (R2016b)

When I start Matlab R2016b my CPU usage at idle is in a range of about 25 % even though I don't do anything on the PC. The Processor I use is a Intel Core i5-6300.

I already tried to set the Help Browser to use the HTMLRenderer, even though I have read that this shouldn't be an issue since the 2015 releases: com.mathworks.mlwidgets.html.HtmlComponentFactory.setDefaultType('HTMLRENDERER');

I don't have any issues when I start Matlab 2013b.

Answer 1

[Arnav Mendiratta]

It is hard to tell the cause of this behavior without information about your system or whether some code is running.

Here are the plausible causes:

- Low on-system RAM

- Loading some data or executing commands in 'startup.m'. You could rule out this possibility by checking if you have any commands in your 'startup' file. To open this file, execute the following command in MATLAB Command Window:

    >> edit startup

- Interaction with graphics card. Certain graphics card and drivers have been known to cause this issue. If it is a graphics issue, you can switch to 'softwareopengl' to resolve this. If you have figured out this is indeed a graphics card issue, the best idea would be to update your driver to latest version (or roll it back to previous version if you have the most updated one.)

- Certain users have reported performance issues on Windows 7, when they have set up "Aero" theme. If you are using this windows theme, consider changing it to see if it resolves the issue.

- Run a benchmark by typing "bench" in the command window. It will show the performance of some standard algorithms on your computer.

If you are still facing issue, you can contact The MathWorks' Technical Support team by creating a new help ticket: http://www.mathworks.com/support/servicerequests/create.html

[pSchi]

Actually it was healed after an update of Windows…

Thank you for your detailed answer!

[Chris Steenhoek]

I've had this problem on my laptop (not an issue on my desktop workstation) using the R2016a/b versions of Matlab. Changing from Windows 7 "Aero" theme to Windows 7 Basic resolved this problem for me. My laptop is a Dell Latitude with Core i7-6600U w/ 16GB and built-in HD Graphics 520. By comparison, my desktop has a Core i7-4790 w/ 32GB and has an NVIDIA Quadro K4200 graphic card.

Answer 2

[Johannes Töger]

I had the same problem on Windows 10 64-bit, both on R2014a (that we use for some legacy software) and R2018b.

It turns out that in my case, the idle CPU use was caused by an automatic Java update. For some reason, the MATLAB_JAVA environment variable was pointing to the Oracle version in C:\Program Files\Java\(something). After changing it to the default version shipped with Matlab R2018b (set MATLAB_JAVA to C:\Program Files\MATLAB\R2018b\sys\java\jre\win64\jre, or wherever your installation is located), I haven't had any problems with the idle CPU use.

Answer 3

[Ramesh G T]

Paste this command in the command window everytime you start MATLAB : com.mathworks.mlwidgets.html.HtmlComponentFactory.setDefaultType('HTMLRENDERER');

My MATLAB uses almost 0% cpu when it is idle.