GTA 5 patch 1.28 seems to have caused problems for PC players.
Both GTA Online and GTA 5 have been affected by performance issues following the release of update 1.28.
The issue was first flagged by modders and mod users, but has been found to occur even if the player is not currently using, or never has used, any mods.
In a Rockstar Support thread tracking the problem, the publisher said it’s looking into the issue.
“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,” Rockstar said.
You can subscribe to the support thread for updates on the issue.