I couldn't imagine using Windows 7 compared to 10, 10 is so much smoother.
Not sure how you mean smoother - I've Windows 10 and 7 running side by side and 7 is perfectly smooth, most operations are efficient in terms of input, etc. though I can see how 10 can be an improvement if you use search and key presses a lot to navigate to things (I personally don't). I actually find 10 an eye sore compared to 7 (I'm using aero glass with a dark charcoal type UI theme but not like the dark/night themes people use).