Photoshop poor display quality while working, why?

Question

Adobe Photoshop

Good day to all!
I recently moved to a new version of PS - CC 2017. Almost immediately I noticed such a thing that when working, those things are constantly displayed that disappear when magnified, but I did not pay much attention to this. Then I began to notice that when you increase or decrease the display percentage, the image itself changes in quality to a terrible one. For example, I created 2 vector objects, with an increase of 500%, the edges of the object become a ladder. After that I save and transfer to AI, everything is in order there. Maybe you need to improve the quality of the display or something else?
And another question regarding bitmap images. I noticed such a thing that if you add an image to AI and reduce it, then the quality of the image does not deteriorate as much as in the same PS, if you can explain in detail why so?

Answer 1

AI vector editor. Photoshop raster. The vector elements in it are not exactly vector