01.Why does GTA IV run so poorly on PC?
Released in 2008, GTA IV was made for DirectX 9. Windows 10 and 11 don't handle the game's old draw calls well, causing it to lag even on an RTX 4090. Additionally, the game has conflicts with processors that have many cores.
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02.The Miracle of DXVK (Vulkan)
This is the SINGLE step that will triple your FPS. It translates the game from DX9 to Vulkan.
- Download DXVK from the official GitHub.
- Extract the
d3d9.dllanddxgi.dllfiles from the x32 folder. - Paste these files into the main game folder (where
GTAIV.exeis located). - Open the game. You'll notice that GPU usage will go up and the FPS will become much more stable.
03.GTA IV FusionFix: The Mandatory Mod
FusionFix fixes errors that Rockstar never fixed, like aspect ratio and flickering shadows.
- Fixes the problem of streetlights disappearing at a distance.
- Allows you to skip boring intros automatically.
- Fixes the crosshair bug in 4K resolutions.
- Just download the .zip file and drop the content into the game folder.
04.Fixing the Memory Error (VRAM)
If the game says you don't have enough video memory (even if you have 8GB), create a text file called commandline.txt in the game folder and paste this inside:
-availablevidmem 4096 -nomemrestrict -norestrictions
Don't do it Manually.
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Written by a verified expert
Douglas Felipe M. Gonçalves
Expert in Windows system optimization with years of experience in hardware diagnostics, kernel tuning, and advanced technical support. Founder of Voltris and developer of the Voltris Optimizer.
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By following this guide on GTA IV Fix: How to Run Smoothly on Windows 10 and 11 (2026), you are equipped with the verified technical knowledge to solve this issue with confidence.
If you still have difficulties after following all steps, our expert support team is available for a personalized remote diagnosis. Every system is unique and may require a specific approach.