# gta4-rtx makes Grand Theft Auto IV work with NVIDIA RTX Remix > gta4-rtx is a compatibility mod that lets Grand Theft Auto IV: The Complete Edition run under NVIDIA's RTX Remix path tracing, with its own runtime fork, an ASI loader, a FusionFix fork and a baseline remix mod. It is emphatically not a remaster, the author says so in the first line of the overview, and the CPU bottleneck it creates is the first thing the documentation warns about. **xoxor4d/gta4-rtx** — GTAIV RTX Remix Compatibility Mod - Repository: https://github.com/xoxor4d/gta4-rtx - Stars: 807 · Forks: 22 - Language: C++ - License: not declared - Published: 2026-10-20 · Updated: 2026-10-20 · Language: en - Canonical page: https://hysenlabs.com/projects/xoxor4d-gta4-rtx ## The mod intercepts draw calls, and the README says that is costly The overview opens with a clarification that everything else depends on: this is not a remaster. It is a mod that allows the game to be modded with NVIDIA's RTX Remix. The reason for the caveat is stated a few lines further down. RTX Remix has an overhead because of how it works, since it intercepts the game's draw calls, and there are obvious drawbacks and things that will not work with such a new title. The author's advice is not to expect perfection. The specific performance claim is about the CPU rather than the GPU. You will likely experience a CPU bottleneck because of the amount of detailed meshes the game is rendering, which means the performance in certain places is not entirely due to path tracing. The bad list repeats the point and notes that Nvidia is constantly updating RTX Remix and has already made changes to improve it. Other drawbacks are listed plainly. The game can be stuttery when traversing the world, and there is no blood on pedestrians. So the honest framing for anyone evaluating this is a lighting and materials upgrade with a CPU cost and some visible gaps, not a performance win. ## Four separate pieces have to be in place at once The compatibility mod is not a single file. It ships with a Baseline Remix Mod from the same author and with GTAIV-AutoPBR, and it comes with a custom Remix Runtime required for a few game specific features. The runtime is a fork of the DXVK Remix project with a branch named for the game's atmosphere variant. Loading the mod into the game is done with Ultimate ASI Loader, and the mod uses a custom fork of FusionFix tailored for RTX Remix rather than the standard FusionFix. That gives four dependencies to install and keep in step: the compatibility mod itself, the baseline remix mod, the custom runtime, and the FusionFix fork, with the ASI loader underneath all of it. The README also notes that DLSS 5.0 support exists if you provide the necessary dll, with the integration contributed by Sparkles and pointing at a separate DXVK Remix branch. DLSS 4.5 with Ray Reconstruction 2 support is listed as a straightforward feature of the mod. Uninstalling is comparatively simple. You delete `d3d9.dll` and `a_gta4-rtx.asi`, or use the provided `_toggle-gta4-rtx.bat` to quickly toggle RTX Remix. The README warns that some other minor files remain in the updates folder, mainly `.img` files starting with `1__remix`, and that if you used the custom fork you should re-install the official FusionFix mod. ## The F4 menu and the affinity batch files are the actual user interface Usage is short because most of the interaction happens in game. You run the game as normal, and press `F4` to open the in-game GUI for compatibility tweaks and debug settings. The feature list mentions many tweakable settings through that in-game `F4` menu, alongside Screenshot Mode, FreeCam Mode and other utilities. There is one thing worth setting up before playing. If you notice heavy stuttering, the README says to launch the game with the included `_LaunchWithProcessorAffinity_2Cores_GTA4.bat`, which assigns 2 cores to GTA4 and the rest to Remix. If you want a 50/50 split, there is a separate `_LaunchWithProcessorAffinity_Half_GTA4__Half_Remix.bat`. This is a direct response to the CPU bottleneck described in the overview. Rather than letting the game and the path tracer fight over every core, you pin the split. It is a blunt instrument, and it will cost you game performance in exchange for smoothness, which is a trade the mod's author clearly expects some users to want. Inside the TUI, or rather the in-game overlay, the same idea of giving the user control extends to the light translation system. All game lights, including the sun, are translated to Remix lights, and you can create overrides for translated game lights, changing position, color and intensity. ## Compiling from source means submodules, VS22 project files and a DLL rename If you would rather build it than download a release, the README gives a short sequence. Clone the repository with submodules: ```bash git clone --recurse-submodules https://github.com/xoxor4d/gta4-rtx.git ``` Optionally, set up a global path variable named `GTA4_ROOT` that points to the game folder where GTAIV.exe is located. Then run `generate-buildfiles_vs22.bat` to generate the Visual Studio project files, and compile the mod. The repository root holds that batch file alongside a premake5.lua script, which is how the project files are generated. If you did not set up the global path variable, you rename `gta4-rtx.dll` to `a_gta4-rtx.asi` and copy it into the game directory next to GTAIV.exe. If you have not installed a release build before, you also copy everything within the `assets` folder into the game directory. And you must make sure to install gta4-rtx-base-mod as well. That last point is worth repeating, because it is the sort of step that gets skipped and then shows up as a visual bug rather than a crash. The baseline mod is a separate repository and a separate install. The source layout mirrors the three logical parts of the project: src/ for the mod itself, src_installer/ and assets_installer/ for the installer and updater that the feature list mentions, assets/ for the shipped content, deps/ for dependencies, and tools/ for supporting scripts. ## The feature list is long, and the omissions are visible in it The good list covers more than lighting. There is an atmospheric sky system with volumetric clouds from the community Remix Plus and Numos work, most objects rendered via fixed function to increase performance compared to grabbing data from vertex shaders, and cascaded anti culling of meshes. The detail work is where the author's own effort shows. Vehicles now have two headlights and two rear lights instead of single centered ones, dynamic emissive surfaces work for vehicle lights, building windows and shops, dynamic wetness works similarly to the original game but only outdoors with falloff on angled surfaces plus raindrops and impacts, and there are raindrops on vehicles and character clothing. Working vehicle dirt and livery are listed, and the mobilephone works, though it is 3D and currently scales with the camera field of view. There is also a modified vertex shader based on FusionFix so that Remix can capture surface normals, and the ability to spawn unique marker meshes that can be hidden based on distance, weather or time of day, used to attach Remix replacements or scene lights. Two features need a third party to work. DLSS 5.0 needs the necessary dll, and the DLSS 5.0 integration comes from a separate DXVK Remix branch by Sparkles. The weather and volumetric clouds come from the community Remix Plus and Numos project, not from this repository. Both are credited, but neither ships here. ## Release cadence is steady, but the licence is not stated The project is not archived and the last push was on 2026-09-03, with three releases in quick succession at the end of August: v1.5.0 and v1.5.1 on 2026-08-30 and v1.5.2 on 2026-08-31. A pace of several releases a week during a development push is normal for a mod of this kind, since a single change in RTX Remix itself can force a rebuild. That last point explains the dependency structure better than anything else in the documentation. The runtime is a fork, the FusionFix is a fork, and the upstream project is being updated constantly. When Nvidia changes something, the fork has to follow, and the CPU bottleneck the author describes is exactly the kind of thing that gets patched upstream rather than in the mod. The licence is not stated in the repository listing, and the README does not spell out a licence either. For a mod that bundles a custom fork of FusionFix and a fork of the DXVK Remix runtime, that matters if you intend to redistribute a build, and it is worth asking the author rather than assuming. The repository also links a wiki with troubleshooting, in-depth guides, usage information and notes on remix runtime changes, which is where the day-to-day knowledge lives. The credits list runs to NVIDIA's RTX Remix, the Discord community including Nvidia engineers, Dear ImGui with a blur effect, minhook, toml11, Ultimate ASI Loader, miniz, Rapidjson, DiscordRPC, FusionFix, FusionShaders, the Rage Shader Editor, the IV-SDK and its .NET counterpart, and a set of individual contributors. ## Conclusion Adopt gta4-rtx if you own Grand Theft Auto IV: The Complete Edition at version 1.2.0.59 on an NVIDIA RTX card and specifically want ray traced lighting, because the mod exists to make an existing game feed the RTX Remix pipeline. Skip it if you were expecting a remaster or a frame rate improvement, since the README states this is not a remaster and that the result is CPU bottlenecked. Verify first that your game version matches, that you install the separate gta4-rtx-base-mod as the README requires, and that you are comfortable with an ASI loader and a custom fork of FusionFix replacing the official one. ## FAQ ### Is gta4-rtx a remaster of Grand Theft Auto IV? No. The README states first and foremost that this is not a remaster, it is a mod that allows the game to be modded with NVIDIA's RTX Remix. The author also warns that RTX Remix intercepts draw calls, so there are drawbacks and things that will not work. ### Which version of Grand Theft Auto IV does gta4-rtx support? The README states compatibility with Grand Theft Auto IV: The Complete Edition, version 1.2.0.59. ### Why does gta4-rtx stutter, and what can I do about it? The README says the mod is CPU bottlenecked because of the amount of detailed meshes being rendered, and that it can be stuttery when traversing the world. If you notice heavy stuttering, it says to launch the game with the included `_LaunchWithProcessorAffinity_2Cores_GTA4.bat`, or the 50/50 split variant. ### What else do I need to install alongside gta4-rtx? The README requires gta4-rtx-base-mod as a separate install, and the mod also uses a custom Remix Runtime, Ultimate ASI Loader and a custom fork of FusionFix. When compiling from source you also copy the contents of the assets folder into the game directory. ## Sources - [Issues](https://github.com/xoxor4d/gta4-rtx/issues) - [README](https://github.com/xoxor4d/gta4-rtx/blob/master/README.md) - [Releases](https://github.com/xoxor4d/gta4-rtx/releases) - [xoxor4d/gta4-rtx on GitHub](https://github.com/xoxor4d/gta4-rtx) --- Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/xoxor4d-gta4-rtx