Excel for Mac high CPU usage problem

Question

Hello,

I have a 120 MB Excel file. Approximately 620,000 rows and 34 columns. I am having a hard time doing anything. Even going from the leftmost column to the rightmost column in one go takes more than 10 seconds. CPU usage is around 150%. Is there a solution for this? Excel and MAC OS are up to date. I am using a MacBook Air with an M2 processor and 8 GB RAM.

Answer 1

Hello Barbaros Şen,

Good morning,

Welcome to Microsoft Community, we are here to help

Thank you for bringing this to our attention, I understand that you need assistance with your Excel high CPU usage issue and to address high CPU usage in Excel for Mac, here are some effective troubleshooting steps:

1. Check Your Workbook: Large files with complex formulas or volatile functions (like NOW or INDIRECT) can strain resources. Simplify your workbook by reducing data size or replacing such functions.
2. Monitor System Resources: Use Activity Monitor to see if Excel is the main culprit. Close unnecessary apps and clear the clipboard (search for "pboard" in Activity Monitor and stop the process).
3. Boot in Safe Mode: Restart your Mac while holding the Shift key. This disables third-party apps and fonts, helping identify external factors causing the issue.
4. Validate Fonts: Open Font Book to check for corrupted or duplicate fonts. Remove problematic ones and restart Excel.
5. Adjust Excel Settings:
   • Disable hardware acceleration.
   • Remove unnecessary add-ins.
   • Switch to manual calculation mode for large datasets.
6. Recreate the file: If issue is still present after doing the steps above, then I suggest recreating the document to isolate whether the issue is within the Workbook or within the formulas

Hope this helps!

Best Regards,

JK

Microsoft Community

Moderator

Answer 2

After cogitating for a day I realize I forgot to mention some other things that can slow things down. The file system your Mac is using can have a large influence. If your file is saved to your Mac's startup volume and there are no other file systems connected, that's the fastest.

As soon as you start connecting devices you can start experiencing slowness. An attached drive that is formatted with Mac OS will not cause much slow down if it has low latency. But the moment you start connecting other file systems like iCloud, Google drive, Box, OneDrive, SharePoint, Windows server, and the like you will experience slow downs, especially if you open the workbook while it resides on a different drive. But simply having other systems connected can be a drag on your speed.

Answer 3

Hi

When working with large content worksheets there are some things you can do to speed things up. The default .xlsx file format is text, but Excel does everything in binary. Saving in .xlsx requires conversion between text & binary and takes time and resources. Use the native Excel binary format .xlsb by using File > Save As and choosing Excel Binary (.xlsb) in the Format pop-up.

JK pointed out that if Calculation is set to Automatic, every tiny change makes the entire worksheet recalculate. Set it Calculation to manual in Excel Preferences unless you need instant calculation results all the time. Also in Excel calculation preferences turn on the setting to enable multi-threaded calculation.

Watch the memory part of Activity Monitor and see if your Mac is using "Swap." If it is, Swap memory is much slower than RAM and can make things feel sluggish. Close other applications and processes to give more resources to Excel.

Answer 4

Hello

We haven't heard from you, so we assume that your issue has already been addressed. We will not be monitoring this thread moving forward so, if you need further assistance, please create a new thread to discuss these concerns by clicking this link: Create a new question (microsoft.com)

Thank you for understanding.

Best Regards,

JK

Microsoft Community

Moderator