The Grand Theft Auto V PC release has started experiencing performance problems in the form of frame rate issues after the title update 1.28. The Update was forwardly known as Ill Gotten Gains: Part 2 and included new cars, guns, clothes and more.
Rockstar has acknowledged that it is aware of the performance drop and confirmed that they are actively looking into the reports. The developer has not provided hints at what could be causing the performance problems, any work around or any eta on when they will have the problem resolved at this time.
Grand Theft Auto V is available on PC, PlayStation 3, PlayStation 4, Xbox 360 and Xbox One, Ill Gotten Gains: Part 2 is the second of two free content updates for GTA Online.