bg3fgvk

Free, open-source DLSS Frame Generation (x2 / x3 / x4) for Baldur's Gate 3 on Vulkan. Compatible with DLSS 5 (NVIDIA Neural Rendering) through OptiScaler, see DLSS 5 below.

Download: Nexus Mods or the GitHub Releases page.

Compatible with the Baldur's Gate 3 Script Extender (BG3SE) and Mod Configuration Menu (MCM).

bg3fgvk is a small DLL that plugs NVIDIA Streamline's DLSS-G into the game's Vulkan swapchain. The game's own DLSS Super Resolution provides depth and motion vectors; the NVIDIA driver generates and paces the extra frames. No upscaler replacement, no menu of its own, no account or key.

Measured on an RTX 50-series card at 2560x1440 with DLSS Quality: a 30 to 35 fps scene shows at roughly 120 to 140 fps with x4 (Streamline itself reports the multiplier).

Quick start

1. Install Native Mod Loader: extract its bin folder over the game's bin folder (the one with bg3.exe) and let it replace bink2w64.dll. It loads every DLL in bin\NativeMods\. Skip if you already have it.
2. Download bg3fgvk-vX.Y.Z.zip from the Releases page and extract its contents into that same bin\ folder, merging the NativeMods folder. You end up with bin\NativeMods\fgvk.dll and bin\NativeMods\Streamline\ (NVIDIA's runtime, seven files; leave the folder where it is).
3. In the game's Video settings the renderer must be Vulkan and DLSS on (any quality, or DLAA). Windows must have Hardware-accelerated GPU scheduling on.

Load a save. Frame generation starts by itself a couple of seconds into the world. Numpad * turns it off and on. That is all.

Requirements

GPU	NVIDIA RTX 40 series for x2 (x3 / x4 possible, see below). RTX 50 series for x3 and x4.
Game	Baldur's Gate 3 in Vulkan mode (the default bg3.exe, not DirectX 11).
In-game	DLSS enabled in Video settings (any quality, or DLAA). With DLSS off the mod stays idle.
Loader	Native Mod Loader (the bink2w64.dll replacement).

RTX 40 series: NVIDIA caps Ada at x2. The community ReShade add-on MFG Ada Unlock lifts it; then set DLSSGFrames=3 for x4.

Checking that it works

On first launch the mod writes bin\NativeMods\fgvk.ini with defaults and a log, bin\fgvk.log. Frame generation turns on about two seconds after the 3D world starts rendering and suspends on loading screens, videos and full-screen menus, where the game does not run DLSS. The log shows:

gate: 60 consecutive DLSS-SR frames -> DLSS-G ON
FG stats: 300 presents -> 1200 frames displayed (x4.00) status=0

x4.00 is Streamline's own count of displayed frames per rendered frame. The game's FPS display cannot see generated frames; use the NVIDIA App or Steam overlay. x1.00 while playing: see Troubleshooting.

Hotkeys

Key	Action
Numpad *	Frame generation on / off
End	Cycle x2, x3, x4

If the NVIDIA App has a per-game DLSS Override, Frame Generation setting for Baldur's Gate 3 (for example "4x"), it pins the multiplier and End appears to do nothing. Set it to "Use 3D application setting" to let the mod decide. It works either way.

Advanced settings (multiplier, Reflex mode, hotkeys) live in bin\NativeMods\fgvk.ini, written with defaults on first launch and documented in BUILD.md.

What to expect

• The displayed frame rate is roughly 4x, 3x or 2x the rendered one.
• A little more input latency than without frame generation; Reflex Boost keeps it in check. 30 fps rendered or more is where x4 looks good; below that, x2 or x3 is the better trade.
• It pauses when the window loses focus, on loading screens and in videos, and resumes by itself.
• Very fast camera pans can show light smearing. That is the technique, not a bug.

DLSS 5 Neural Rendering (optional)

bg3fgvk runs together with DLSS 5 through the OptiScaler_DLSSNR fork of OptiScaler. OptiScaler passes the game's DLSS call through to the driver and runs the Neural Rendering model over the upscaled image; bg3fgvk reads that same call, so the generated frames carry the result. RTX 50 series only, and you must supply NVIDIA's nvngx_dlssnr.dll yourself (the RenoDX Discord distributes it with its DLSS 5 add-on). Setup and the ini keys that matter are in docs/DLSS5.md.

Troubleshooting

Diagnostics are bin\fgvk.log (this mod) and bin\sl.log (Streamline).

• FG stats shows x1.00 while playing. No gate: ... DLSS-G ON line means the game is not running DLSS: enable it in Video settings. BG3 silently drops the DLSS setting after a failed init, so re-select it. status=2 means Reflex is off (ReflexMode in fgvk.ini must be 1 or 2); status=1 means the resolution is too low. The window must have focus.
• The game does not start, or the log stops after slInit. Streamline files missing from bin\NativeMods\Streamline\ or mixed from two versions, or Hardware-accelerated GPU scheduling is off.
• Black screen or freeze. Another mod that hooks Vulkan (an overlay, another frame generator) is the usual cause; sl.log shows WaitSemaphores ... timed out right before the stall. OptiScaler's menu with frame generation on froze the game in bg3fgvk 0.1.0; 1.0.0 fixes it. Attach both logs to a report.
• Script Extender mods stop drawing their UI. Not expected; report it with the logs.

Developers: build steps, how it works, the Streamline runtime files and the stack dumper are in BUILD.md.

Credits and licenses

• bg3fgvk is released under the MIT License (see LICENSE).
• The NVIDIA Streamline SDK 2.12.0 runtime (sl.*.dll, nvngx_dlssg.dll, NvLowLatencyVk.dll) is bundled unmodified from NVIDIA's release package under its license, included as STREAMLINE-LICENSE.txt. Copyright NVIDIA Corporation.
• Microsoft Detours (MIT) for the hooks.
• Norbyte's Baldur's Gate 3 Script Extender, which this mod is built to coexist with.
• PureDark's frame generation mod for Baldur's Gate 3, whose DLSS-G input recipe served as the reference for what the game's buffers look like.
• Dagherbou's OptiScaler_DLSSNR fork, which makes the optional DLSS 5 setup possible.
• !FingerPaint, who found that the OptiScaler_DLSSNR fork and bg3fgvk work together and reported the combination.