The author from the YouTube channel FriendlyBaron has published a video dedicated to the speed passage
One of the main factors in reducing the required time for a quick passage of GTA V was the release of the PC version. Thanks to the presence of graphics settings, speedrunners removed from the world many objects that interfered with the character and could slow him down. Already in the prologue, it is clear that now, after committing a robbery, players quickly run to the car with their partners, shooting police cars. The fourth mission shows how lowered graphics settings on PC can gain valuable seconds by loading cutscenes faster.
Many of the methods for reducing the passage since 2014 no longer work, but speedrunners are constantly finding new ways to reduce the rates. To date, the record for completing a story campaign in GTA V is a little over six hours.
Source: 3dnews.ru