Can I record an 8K virtual desktop with a 1080p or 1440p interface size?

BetterDisplay’s virtual-screen HiDPI modes use a fixed 2× backing scale. An 8K backing image of 7680 × 4320 therefore corresponds to a 3840 × 2160 logical desktop, not a 1920 × 1080 or 2560 × 1440 desktop.

The macOS scaling explanation distinguishes desktop size, rendering pixels and physical output.

The logical resolution determines how much desktop space you have. HiDPI renders twice as many pixels along each axis:

Choose the desired HiDPI mode from the virtual screen’s Virtual Screen Mode menu. Selecting 7680 × 4320 LoDPI instead produces a very large logical desktop, which explains why windows and text appear tiny when you view the whole image. Changing the reported diagonal size does not introduce a 3× or 4× backing scale.

For a comfortable 1440p desktop, use 2560 × 1440 HiDPI and its 5K backing image. If you need an 8K backing image, use an available 3840 × 2160 HiDPI mode and enlarge content within the application where supported. Available modes still depend on the virtual-screen configuration and the Mac’s limits.

Select the virtual screen in your recorder and check the dimensions of a short sample recording. Capture and export settings can resize the result. Mirroring or viewing that desktop on a smaller physical display does not change the logical-to-backing relationship. See creating a recording desktop and HiDPI performance.