Hi,
Mouse scroll speed depends on what option did you assign on your device. You can adjust it to make it faster or slower. To do this, visit this link: How to change Mouse Scroll Speed in Windows 10 for instructions.
Let us know if you have other concerns.
Although my Page Down problem seemed to have nothing to do with a mouse (since I don't use one), I decided to try the suggestions nevertheless. I tried every setting in multiple combinations - nothing worked.
My original post is referring to the Page Down which is integrated on my number pad. As I said, it only happens with articles viewed through the MSN.com news feed. Google, AOL & Yahoo news feeds do not have this problem.