Performance Settings in the Unreal Engine Project Settings | Unreal Engine 5.5 Documentation

Performance

Section	Description
Default Screen Percentage Mode for Real-Time Editor Viewports	You can choose from the following options: Manual: Directly controls the screen percentage with the `r.ScreenPercentage` CVar. Based on Display Resolution: Automatic control of the screen resolution based on the display resolution,`r.ScreenPercentage.Auto.` Based on the Operation System's DPI Scale*.
Default Screen Percentage Mode for Non-Real-Time Editor Viewports	You can choose from the following options: Manual: Directly controls the screen percentage with the `r.ScreenPercentage` CVar. Based on Display Resolution: Automatic control of the screen resolution based on the display resolution,`r.ScreenPercentage.Auto.` Based on the Operation System's DPI Scale*.
Manual Screen Percentage to Be Set by Default for Editor Viewports	Manual screen percentage to be set by default for editor viewports.
Minimum Default Rendering Resolution to Use for Editor Viewports (in Pixels)	Minimum default rendering resolution to use for editor viewports.
Maximum Default Rendering Resolution to Use for Editor Viewports (in Pixels)	Maximum default rendering resolution to use for editor viewports.