Optimized themes (SEO / PageSpeed)

Mr. Jinx

Well-known member
I was wondering if there currently is any theme that is better and faster than XF's default theme?

For example, I like the UI.X 2 theme from ThemeHouse, but it feels slower or more bloated than XF's default theme.
It also does not give a good score with PageSpeed.
So are there any really optimized themes out there with focus on mobile speed?