The Optiscaler team keeps moving at a pace that’s hard to keep up with. Just when it feels like the feature list can’t get any more useful, another test build drops with something the community has been asking for since day one: a practical way around FSR 4’s biggest limitation for many PC players.
This latest update tackles the long-standing “Vulkan wall.” For close to a year, getting FSR 4 working in Vulkan games has effectively been a no-go. The what and why behind that limitation has never really mattered to most players nearly as much as the outcome: no clear progress, no roadmap, and no official solution. Add in the ongoing frustration around the missing INT8 version of FSR 4, and it’s easy to see why so many people have been looking to community tools for answers.
Optiscaler’s approach doesn’t magically remove the underlying limitation that blocks native FSR 4 support in Vulkan. Instead, it introduces what’s best described as a compatibility path. In other words, it creates an interoperability layer that lets Vulkan titles feed the right kind of data into Optiscaler’s pipeline so you can still end up with an FSR 4-style result. The deeper technical specifics haven’t been fully laid out yet, but the real headline is simple: Vulkan games are no longer automatically excluded.
What you need before installing Optiscaler
To get started, you’ll want:
1) OptiScaler v0.9.0-pre10 test build (or newer)
2) OptiPatcher (specifically the Optipatcher.asi plugin file)
OptiPatcher is important here not only for compatibility and performance (it’s generally a better route than older spoofing methods), but also because the current Optiscaler setup process in recent test releases may hang at the final step without it. Even if a Vulkan title might technically work without OptiPatcher, using it tends to make the installation smoother and the results more reliable.
Example install: Indiana Jones and The Great Circle (Vulkan-only)
The only part that really changes from platform to platform is where the game’s executable lives. The rest of the process is basically the same.
Step 1: Find the game executable
If you’re on the Game Pass version, the quickest route is:
Open the game in your library → open the menu → Manage → Files → Browse
That will land you in the XboxGames install directory. Open the folder for the game, then look for the executable in its Content folder. In this case, the executable is TheGreatCircle.exe.
Step 2: Copy Optiscaler files into the game folder
Extract Optiscaler, then copy everything from the extracted Optiscaler folder directly into the same folder where the game’s executable is located.
Step 3: Add OptiPatcher
Inside that same game folder (the one with the .exe), create a new folder named:
plugins
Then place:
Optipatcher.asi
inside that plugins folder.
Step 4: Run the Optiscaler setup script
In the game folder you copied Optiscaler into, find:
setup_windows.bat
Run it. If Windows throws a security warning prompt, choose to run it anyway.
When prompted, enter the following choices (press Enter after each):
2 (select winmm.dll)
2 (select AMD/Intel)
2 (no spoofing)
n (don’t update Optipatcher)
When it finishes, press Enter to close the script. Optiscaler should now be installed.
In-game configuration (the part most people miss)
Launch the game and go to Video settings. Set the game’s upscaler to either FSR or DLSS. This setting is mainly about what input Optiscaler receives. Many players find the DLSS input can look better, but it may be less stable in some games, so it’s worth testing both.
Once you’re in gameplay, press:
Insert
That opens the Optiscaler menu.
In the Upscalers section (top left), click XeSS to open the dropdown list. Then:
Select “FSR 3.X w/Dx12”
Click Change Upscaler
That specific selection is the key that enables the Vulkan interoperability layer. If everything is working correctly, FSR 4-style upscaling should engage automatically afterward.
Performance angle: why Vulkan support matters (Red Dead Redemption 2 example)
Red Dead Redemption 2 is a great real-world case for why this Vulkan breakthrough is so valuable. The game’s anti-aliasing is infamous for producing a soft, blurry image in motion, and better upscaling can help clean that up substantially.
Yes, RDR2 also supports DX12, and DX12 already works with FSR 4 through Optiscaler. But DX12 can introduce stuttering and uneven frame pacing in some sections for some systems, while Vulkan often runs smoother. So the ideal setup for many players becomes clear: FSR 4-quality output paired with Vulkan’s typically steadier frame times.
Installing for RDR2 (Steam) starts the same way: go to the game in your library, click the gear icon, then Manage → Browse Local Files to reach the install directory. Copy Optiscaler files in, create the plugins folder, and place Optipatcher.asi inside it.
One important warning for RDR2: Rockstar’s launcher can interfere with OptiPatcher and cause it to break. That means RDR2 may require extra steps beyond the standard process to avoid launch failures or a non-working injection. If you want, tell me which version you’re using (Steam or another platform) and what GPU you have, and I can rewrite the RDR2 section into a complete, start-to-finish installation path that accounts for the launcher issue and avoids the most common failure points.If you’ve been trying to get FSR 4 working properly in Red Dead Redemption 2 on Vulkan, you’ve probably discovered the annoying reality: it isn’t as simple as flipping a toggle. The upside is that there’s now a reliable way to make it work, and it comes down to combining Optiscaler with a small but important helper that fixes plugin loading.
The stumbling block for many players is that when you use Optiscaler to spoof DLSS inputs (which is the key for getting the best results here), the game may fail to load the necessary plugins correctly. The fix is a “workaround to the workaround” in the form of Ultimate ASI Loader. All you need from it is the dinput8.dll file. Download it, extract it, and copy only that .dll into your Red Dead Redemption 2 folder. After that, you can install Optiscaler using its setup script (windows_setup.bat) just like you normally would.
Once you’re in-game, the setup process stays the same as well, with one crucial detail: make sure you’re using DLSS inputs rather than FSR2 inputs. That choice matters for getting FSR 4 to behave the way you want, especially in Vulkan.
To see what this actually looks like in terms of performance, testing was done at 4K using Ultra settings with FSR 4 set to Quality. The test system included an i7-13700K, 32GB of DDR5-7200 memory, an RX 9070 XT Mercury, two 1TB SN850X drives, a Liquid Freezer II 420mm cooler, and a Seasonic Focus GX 1000W power supply.
A short performance loop through Saint Denis showed a clear split between the two graphics APIs. DirectX 12 came out ahead on raw FPS, running about 10% faster with an average of 88 FPS compared to Vulkan’s 80 FPS. But the real story wasn’t the average framerate—it was the smoothness. DirectX 12 suffered from frequent stutters, with frametime spikes jumping up to 20ms and sometimes beyond 30ms. Vulkan, on the other hand, delivered a much more consistent experience with frametimes tightly clustered around the 12.5ms range, which lines up neatly with that 80 FPS average.
In other words, DX12 may win the benchmark chart, but Vulkan wins where it counts during actual play: steadier frame pacing and fewer immersion-breaking spikes.
It’s fair to ask why this even matters. Vulkan-only AAA releases aren’t exactly everywhere, and only a couple of recent big-name games come to mind in that category. So in a purely practical sense, this isn’t a dealbreaker for FSR 4 overall. The bigger frustration is the silence—nearly a year without meaningful communication or any clear timeline for an official fix. Upscaling quality is a major selling point for newer AMD GPUs, and players shouldn’t have to rely on mods just to get “decent” upscaling in a popular title.
Still, the good news is simple: if you’re willing to do a little setup work, Optiscaler now makes FSR 4 genuinely playable on Vulkan. Yes, there’s a performance hit, but it’s not severe enough to erase the value—especially when the image quality improvement in Red Dead Redemption 2 is significant. With Vulkan now working smoothly, the trade-off becomes far easier to justify.
For many players using RDNA 3-class GPUs and newer, Optiscaler is quickly becoming one of those must-have tools for Red Dead Redemption 2, not because it’s fun to tinker, but because the end result looks better and plays smoother. And until AMD provides a proper official solution, it’s likely that this kind of mod-driven path will remain the go-to option for anyone chasing the best upscaling quality in Vulkan titles.
