Action required view is faster.

The good news: We've just now made some improvements to the "Action required by" filter. The improvements have resulted in a substantial speed increase for the "Action required by me" built-in view and any custom views that use that filter when there are many actions. The built-in view is updated automatically. For custom views you have to remove that filter then add it again to see the improvement.

The bad news: As listed on our known issues page, selecting a value of "Nobody" for that filter still doesn't work right.