This design fuels the visually rich and graphical macOS experience as well as many deeper platform compute and graphics features. Mac hardware and GPU software drivers have always been deeply integrated into the system. When the eGPU is re-attached, it automatically sets the external display as the primary display. If you disconnect the eGPU, your Mac defaults back to the internal graphics processors that drives the built-in display. Drag the white menu bar to the box that represents the display that's attached to the eGPU.Click Displays, then select the Arrangement tab.

Choose Apple menu  > System Preferences.

Quit any open apps that you want the eGPU to accelerate on the primary display.

Open the apps that you want to use with the eGPU.

Select the display that's attached to the eGPU, then choose Use as Main Display.

Choose Apple menu  > System Settings (or System Preferences), then click Displays.

Quit any open apps that you want the eGPU to accelerate on the primary display.

Since apps default to the GPU associated with the primary display, this option works with a variety of apps. If you have an external display connected to your eGPU, you can choose it as the primary display for all apps.

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