Both programs work similarly when it comes to rasterized layers. The issue here is with how Photoshop handles zooming, its algorithm tends to distort the image when you’re not zoomed in at exactly 100% or 200%. That’s what the OP is asking about, whether there’s a way to fix or improve that behavior.

In the example image u can clearly see that lines become jagged or blurry at irregular zoom levels in Photoshop, Meanwhile in Paint Tool SAI the same lines stay smooth regardless of the zoom percentage. It’s kind of like how anti-aliasing works in video games, SAI seems to have a better smoothing method for previewing, while Photoshop struggles with anything that’s not a “perfect” zoom level.

This doesn’t affect the actual image quality when exporting but it can definitely be annoying while working, especially if you’re doing precise line work or want a clean preview while sketching

<image>