I've tested the simple config file tweaks to improve Metal Gear Solid Delta's ray tracing and add frame gen, but the mod to ditch the 60 fps cap is what you really need

Metal Gear Solid Delta: Snake Eater, a full remake of the classic MGS 3: Snake Eater, has only just been released for PC and consoles, but that means nothing to modders. Built in Unreal Engine 5, the developers chose to use its standard software ray tracing Lumen algorithm, and they also eschewed supporting frame generation. It turns out that the fix for both of these requires nothing more than adding a few lines to a single config file.

Word of this was reported by Wccftech, and having just spent a couple of hours testing it myself, I can confirm that it all works perfectly. Unreal Engine 5 has two modes for its Lumen global illumination system: software and hardware. The former is designed as a lightweight ray tracing solution that requires no specific RT hardware and sacrifices visual quality for performance.

Hardware-mode does the opposite: the GPU running the game needs to have dedicated components and driver support for ray tracing, as offered by AMD's RX 6000-series, Intel's Arc series, and Nvidia's RTX 20-series, or newer. Hardware Lumen can produce better quality ray tracing, at the expense of performance, and this is why so many ray-traced games also support upscaling and frame generation to counter this.

To adjust this, head over to the following location on your PC's Windows installation:

C:\Users\[...]\AppData\Local\MGSDelta\Saved\Config\Windows

Look for a file labelled engine.ini and open it in Notepad. Scroll all the way to the bottom and then add the following lines of text:

[SystemSettings]
r.Lumen.HardwareRayTracing=0
r.Lumen.Reflections.HardwareRayTracing=0
r.Lumen.ScreenProbeGather.HardwareRayTracing=0
r.LumenScene.DirectLighting.HardwareRayTracing=0
r.NGX.DLSS.denoisermode=0
r.Streamline.DLSSG.Enable=0
t.Streamline.Reflex.Enable=0
t.Streamline.Reflex.Mode=0

The first four are for hardware RT Lumen, the fifth one is for Nvidia's Ray Reconstruction, and the final three are for DLSS frame generation. MGS Delta doesn't have any kind of frame generation setting in its menus and, if I'm to be honest, is pretty barebones in terms of graphics options full stop.

So applying the config file adjustment won't make anything appear in the setting menu, but having stared at my screen for a while (and measured performance), it definitely seems to be enabling hardware Lumen.

I say 'seems' because the difference in visual quality is very slight, or at least it is in the area I've checked out so far, as you can see in the video. The first half is a short run of the game without any of the tweaks added, whereas the second half is applying hardware RT Lumen, Nvidia Ray Reconstruction, and DLSS frame generation.

The footage was captured off a GeForce RTX 5090, in a Core Ultra 9 285K, 48 GB DDR5-8400 test rig. I suspect that while you've possibly struggled to notice the difference that the change in Lumen is supposed to have, you'll almost certainly notice the jump in performance caused by the frame generation. I haven't figured out how to change what level of frame gen is used, but it's enough of a boost for my tastes, as is.

MGS Delta with Lumen and Ray Reconstruction tweaks only

Just a word of caution, if you plan on using these config tweaks yourself, especially frame generation: Metal Gear Solid Delta is, for some unfathomable reason, capped to 60 fps on PCs, so I strongly suggest that you first install Better Uncap FPS v1.4 on Nexus Mods. That requires you to put a bunch of things in one of the game's sub-folders and copy an engine.ini file to the same location as above.

If you've already applied the config tweaks, this new file will override them, so what I did was just copy the relevant parts from the Better Uncap mod and add them to the very bottom of the normal engine.ini file:

[SystemSettings]
t.AllowFrameRateSmoothing=0
rhi.SyncInterval=0
rhi.PresentInterval=0

[RenderingThread]
bAllowThreadedRendering=True
bAllowAsyncRenderThreadUpdates=True

[/Script/Engine.RendererSettings]
r.GraphicsAdapter=0
r.VSync=1
r.OneFrameThreadLag=0
rhi.PresentInterval=0
rhi.SyncInterval=0
r.Streamline.DLSSG.Enable=1
t.Streamline.Reflex.Enable=1
r.Streamline.DilateMotionVectors=0

[/Script/Engine.Engine]
bSmoothFrameRate=False
MinSmoothedFrameRate=0
MaxSmoothedFrameRate=100
bLimitFrameRateToRefreshRate=False

Stick those in the game's engine file, then add the Lumen, RR, and DLSS tweaks to the SystemSettings section and it'll all work peachy. By default, the mod fully removes the frame rate cap, so it can make the game feel a bit stuttery and induce a spot of tearing, but the instructions on Nexus Mods will tell you how to set your own limit.

MGS Delta with original 60 fps limit and RT Lumen, Ray Reconstruction, DLSS frame gen

At this point, you might wonder why Konami didn't choose to use hardware Lumen or offer frame generation. I suspect it was a choice based on simplicity, ie, have every platform version of the game look the same. With a 60 fps cap, there's no point in offering frame generation, and ray reconstruction can only be applied if you use an RTX GPU's ray tracing hardware.

To my old eyes, there isn't a great deal of difference between software and hardware Lumen modes in Metal Gear Solid Delta, but perhaps there is in other sections of the game. Better lighting and reflections are all very nice, of course, but the textures are quite rough-looking and very old-school in places. No amount of ray tracing wizardry is going to fix that, I'm afraid.

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