
This issue first surfaced after a user asked Rockstar why his frame rate began to drop after he installed the latest title update. Rockstar Support responded briefly by saying this, "We have received reports of lower framerate in GTAV and GTA Online after Title Update 1.28 on PC, and we are looking into these reports now." The latest add-on has resulted in frame rates as low as 3-frames-per-second for those running the extremely popular LCPD modification. According to a recent Facebook post from the developers of the LCPD first response mod, the problems were side-effects of new anti-modding measures, that were supposedly introduced by Rockstar in the most recent patch. Despite that this particular modification could be causing massive drops in frame rate, performance issues were additionally reported from players that did not have any mods installed at the time.
This is a continuing story, I will update this article when a fix has been implemented by Rockstar...
GameSpot