Illustrator is extremely slow and laggy, even with simple files

I had almost the exact same thing recently while making a logo for Nurturepedia. My laptop is a 13th-gen i5 with plenty of RAM and free disk space, so I was honestly confused why Illustrator was still lagging on something as simple as a logo.

A couple of things are worth checking. Try turning GPU Performance off in Edit > Preferences > Performance and see if Illustrator becomes more responsive. You can also switch to Preview on CPU just as a test. If that makes a noticeable difference, I’d check/update the NVIDIA and Intel graphics drivers as well. Adobe actually recommends this for GPU-related Illustrator performance problems.

Also, if you’re on a laptop with integrated + dedicated graphics, check that Illustrator is actually using the dedicated GPU. That can make a surprising difference.

What makes your case interesting is that it’s happening even in a completely empty document, so I’d look at the GPU/driver side before blaming the file itself.

If you deleted the preferences in one of the automatic ways with no luck then you might want to try manually deleting them. There are times when this different way of doing the same thing will actually work.

To manually delete preferences in Windows:

The preference files are hidden. To find them go to the Control Panel and open Folder Options and then click the View tab. Then select “Show hidden files and folders” or “Show hidden files, folders or drive options” in Advanced Settings. Then delete (or rename) the folder at the end of this path: C:\Users\[User Name]\AppData\Roaming\Adobe\Adobe Illustrator [version number]\ Settings\<Language>. Make sure that Illustrator is closed when you do this. When you relaunch the program it will create  new preference files and the program will be at its default settings.

A bonus advantage of manually deleting preference files is that after you’ve reset up the program (make sure that no document window is open) to your liking, you can create copies of your personalized “mint” preference files (make sure that you quit the program before copying them—that finalizes your customization) and use them in the future to replace any corrupt versions you may need to delete.