Before diving into solutions, it's essential to understand why GTA IV might be lagging on your high-end PC. Several factors contribute to this issue:
Create a file called commandline.txt in your GTA IV folder and add: Gta Iv Lagging On High End Pc
DXVK solves the stuttering, but FusionFix solves the rendering accuracy. Before diving into solutions, it's essential to understand
Even on a high-end PC, certain settings should be lowered to avoid engine-level bottlenecks: Before diving into solutions
The vanilla fixes alone won't solve "GTA IV lagging on high end PC." You need to replace the graphics API. GTA IV uses DirectX 9. By converting it to Vulkan or DirectX 11, you force the game to use your modern GPU correctly.