Reborn UI low fps only on macOS

A Former User

I'm running Opera Developer 45.0.2531.0 on both Windows and macOS Sierra. I have the same 144 Hz monitor on both systems. The Reborn UI on Windows runs at a much higher frame rate than the older UI in the stable version. However on macOS the Reborn UI is still laggy and seems to be capped at 60 fps even on a 144 Hz monitor.

I posted about the stable version running only at 60 fps in another thread:
https://forums.opera.com/topic/19574/ui-elements-are-laggy-and-animate-at-only-60-fps-on-144-hz-monitor

On macOS, you can clearly observe the Reborn UI running at a low frame rate when clicking on the side bar icons. The "bubble" animation stutters severely. The zoom in and zoom out effect when hovering the mouse over the icons also stutter.