Rookies games can be slow or fast. During the first 2 days users can bet on Rookies participants, each time a user places a bet the game can reconfigure itself to become a slow or fast game. If bets are more or less equally spread among participants the game will switch to fast mode, while if one or few participants get all the bets the game will switch to slow mode.
Fast mode games can be totally finished in minutes as game advances are done when all actions are finished (including jury voting), while slow games will usually last from 3 to 9 days.
Fast Rookies T$ prices do not change between fast and slow games, but Karma in fast games is reduced to one third (aka 5K) as fast games can be finished in a few minutes.
I saw a game yesterday and I watched to see if it was slow or fast and it said SLOW to the right of the counter as soon as the game started. I'm not sure that any of us really knows how it works for sure.