Volumetric clouds can be rendered live now, for awhile actually but more a tech thing until recently. The first game to use it is Assassins Creed Origin. The game throws out new seeds every day, and the shapes progress with time just like a PF. The static sun image even plays nicely through the clouds. xD Volumetric water is also beautifully rendered in-game.
GPU units are amazing for rendering these days. Pretty much the standard.
PS, Assassins Creed Origins and Odyssey are both beautiful games. Very well optimized and run great on even older systems.