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ZoomText/Fusion Performance considerations

ZoomText/Fusion Performance considerations

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You are experiencing performance issues when Fusion is running. Below are some items to consider which may help.


Ensure that the PC or laptop being used confirms to the minimum ZoomText system requirements.

Further points to consider

  • If your system has a 4K screen with a high resolution, change the resolution down to 1920×1080.
  • If you are using a second screen, please connect it directly to your system using an HDMI/VGA/DVI connection, and not through a USB docking station or similar.
  • There are known performance issues with accessibility applications in Windows builds released around 2017 and 2018. Use¬†Windows 10 builds¬†1903 or 1909 or higher if possible, as Microsoft made many performance fixes and fixes for these UIA issues.
  • Update ZoomText as much as you can, and test with the latest version where possible. Performance enhancements are frequently made within updates.
  • Update the system display driver, from the laptop’s manufacturer where applicable rather than from Intel/Microsoft.
  • Disable desktop effects in Windows by going to Control Panel> System> Advanced System Settings>Performance Settings button> “Adjust for best performance”> OK.

Geometric smoothing
The default “Clearsharp” geometric smoothing uses pixel shading which can be intensive on the system’s GPU. Changing Geometric Smoothing to Legacy alleviates this.

  1. Open the ZoomText menu, go to Preferences, then Smoothing.
  2. Set Geometric smoothing to Legacy, and press OK.
  3. Open the ZoomText menu, go to Configuration, then Save as default.

FocusTimerInterval setting
Changing this setting can reduce CPU load. Locate the following file: “C:\ProgramData\Freedom Scientific\ZoomText\2022\ZoomTextConfig.xml” And open this in Notepad. Find the line mentioning:

<Property name="FocusTimerInterval" value="250" /> 

and change the value to 1250 so it reads:

<Property name="FocusTimerInterval" value="1250" /> 

Save and close the file, then restart Zoomtext.

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