Illustrator switching to CPU Outline preview.

Here I have described the solution to the problem:
https://community.adobe.com/t5/illustrator-discussions/zoom-is-different-in-preview-and-outline-smooth-zoom-in-preview-marquee-zoom-in-outilne/m-p/12441749/thread-id/294031

And I made a short video with instructions:
https://youtu.be/tYuhYnfGepw

Adobe help has this to say about Outline mode and GPU preview:

https://helpx.adobe.com/in/illustrator/using/viewing-artwork.html#view_artwork_as_outlines

You can view your artwork as outlines in the GPU Preview mode in Illustrator on screens with resolution greater than 2000 pixels in width or height. Viewing artwork in the GPU Outline mode displays smoother paths and speeds up the time it takes to redraw the complex artwork on high-density display screens.

But it doesn't mention screen size at all in the relevant What's New, when GPU preview was changed to include outline mode:

https://helpx.adobe.com/in/illustrator/using/whats-new/2019.html#AnimatedzoominOutlinemode

Now, the Outline mode is GPU enabled. Viewing artwork in the GPU Outline mode displays smoother paths and reduces the time it takes to redraw the complex artwork on high-density display screens.

For reference, I have a 1920 x 1200 screen and Outline mode shows as "CPU Outline".

I don't know why they wouldn't mention that 2000 px stipulation in the What's New page. It seems like rather a crucial omission.