Why?

Let's be honest here, the engine did not age well. The renderer is based on now 22 year old DirectX 9, which fails to fit-in with modern GPUs and Windows. It's extremely inefficient and CPU bound, has glaring issues with display modes, memory handling and overall stability.
As for Bethesda's code - it also fails (horribly) to scale well with modern processors, something that you can see even in their latest titles.
To make things worse, Fallout: New Vegas was compiled without compiler optimizations, which while making engine modding easier, reduces the overall performance.

In short most performance issues can be summed with two words: CPU bottleneck.

Even with that fact in mind, there are some tweaks to be done on the GPU and presentation side of things that can help with the overall responsiveness of the game, despite not fixing the performance on its own.

Things You Should Know

• Vertical Synchronization (V-Sync) - technology allowing to keep display's scanout and refresh in phase to eliminate screen tearing, at the cost of higher latency.
  (Latency lowers along with refresh rate)
• G-Sync | FreeSync - Variable Refresh Rate (VRR) technologies developed by NVIDIA and AMD respectively. They allow the display to adapt its refresh rate to the framerate, allowing to use V-Sync at arbitrary framerates and reduce its latency^[1] .
• Multiplane Overlays (MPOs) - hardware scanout planes for the GPU. They allow for hardware image composition without any latency or performance penalty (for example displaying windows on top of each other), as well as their hardware scaling and stretching. MPOs are supported since Windows 8.1. Hardware capabilities vary between GPU manufacturers.
• Input Latency (lag) - time between input event (mouse click, keyboard press) and the event being displayed on the screen. The lower the latency, the more responsive the game feels.
  There are multiple sources of latency, varying from GPU/CPU usage, display mode, framerate count and many more - most of them are covered in this guide.

1. Yes, despite popular misinformation, VRR alone doesn't get rid of tearing. It can minimize the rolling tear however, but that varies between displays, and such, it's not a guaranteed feature. Additionally, the latency reduction applies only at framerates below V-Sync window (display's native refresh rate) - if framerate matches the native refresh rate, VRR engages V-Sync emulation.

Rewritten

lStewieAl has made a few of mods focused on improving the engine perfomance in multiple aspects (loading, rendering, AI processing).

Installation

Download and install the following mods with your mod manager:

1. lStewieAl's Tweaks and Engine Fixes
2. Stewie Tweaks - VNV INI (or the Extended INI)
3. lStewieAl's Engine Optimizations
4. Faster Main Menu

Stutter Remover

New Vegas Tick Fix is a mod by karut that fixes and improves game's internal clocks and memory management, which dramatically reduces stutter.
It also allows playing above 60 FPS without breaking physics, although the recommended limit should be set to 120 FPS or below.
Additionally, it has some DirectX changes, which help with performance and greatly reduce memory usage.

Installation

1. Once the mod has been installed, double-click it in the left pane of MO2.
2. In the INI-Files tab, open NVSE\Plugins\NVTF.ini
3. Change the following option:
• Set bModifyDirectXBehavior to 1 if not enabled already.
• Set bUseDefaultPoolForTextures to 1.

This setting Disables texture mirroring between VRAM and RAM, which decreases RAM usage and allows using high resolution textures.

This also breaks Alt-Tab functionality in Fullscreen Mode.^[4]
To mitigate that, either use DXVK, Windowed Mode or just avoid Alt-Tabbing. This is also covered later in the guide.

---

4. D3D9 loses the graphics device if it loses the screen ownership (Alt-Tab, Sleep, etc.). To recover, it needs to either have a copy of textures in RAM, or be able to reconstruct the memory from ground up.
   Fallout: New Vegas, like most D3D9 games, use the first method. Thus by disabling this behavior, after Alt-Tabbing, game is in a limbo where it doesn't know what to do.
   DXVK fixes this by simply being in place of D3D9, while Windowed mode guarantees the game will never own the screen in the first place.

Occluded

Simple mod I made to help in areas like Dead Money or Point Lookout, which are very densely packed with objects, yet have a lot of fog hiding them. Dynamically adjusts draw distance in accordance with the fog to improve performance with little to no visual difference.

Installation

1. Download Fog-based Object Culling and install it with your mod manager.

Compressed

Fallout: New Vegas uses zlib compression for its BSA archives and plugins (NPC and Landscape records).
zlib on its own does not belong to the fastest compression algorithms, and the version used by Bethesda is older than the game itself, which only makes things worse.
By simply updating the library to the latest version, you can cut the time spent on decompression in half, which leads to faster loading times and less stuttering.

Installation

1. Download zlib Updated - NVSE and install it with your mod manager.

Driver Updates

Not much to say here - for the best compatibility and performance, you must be using the newest driver for your graphics card.

You can check what GPU you have by opening Task Manager, and going to the Performance tab - the last GPU in the left pane should be your main one.
If you don't see any GPU there, that means your GPU is too old to use DXVK.

Select your graphics card to go the driver download page
NVIDIA	AMD	INTEL

Multiplane Overlays and Windows Watermark

Make sure your Windows is activated, otherwise the watermark will kick the game into the DWM composition, which leads to increased latency, worse performance and disables VRR.
If you don't have a GPU with MPO (Multiplane Overlay) support, you can mitigate this by disabling Fullscreen Optimizations.
(Keep in mind that this trick won't work on modern, D3D12 games, so it's still recommended to just activate Windows)

How to check if your GPU supports MPOs:

1. Type dxdiag into Windows search
2. Click Save All Information and save the file.
3. Open the DxDiag.txt file, press Ctrl+F and look for MPO MaxPlanes
4. If the number is greater than 1, then your GPU has MPO support.

Virtualization

Windows 11 uses virtualization features to increase system and inter-process security. Unfortunately, this can come at a performance cost, especially on lower-end hardware.
I won't be writing on how to disable them, because... Microsoft already made a tutorial about it.

This step is not mandatory, as when it comes to security, it's up to you to decide. Just letting you know that this exists, and that even Microsoft acknowledges the fact that it can degrade perfomance.

Power Plans and Modes

With Windows 10, Microsoft introduced power modes, which are meant to be replacement for power plans in terms of power and perfomance management.
Power modes require the Balanced power plan to be active to work. If you're any other power plan, you won't be able to use them (On most modern systems, you may find that you don't even have other power plans at all because of this).

To change your power mode, go to Power settings, and select whatever highest performance option you have if the dropdown menu.

Game Mode

Windows 10 introduced a feature called Game Mode, which puts the system in a more gaming-friendly state.
Game Mode is a "power mode overlay", which means it requires power modes to work - the Balanced power plan must be active.

Game Mode features:

• Enables AutoHDR for DXGI based games.
• Enables VRR optimizations for games using Flip Model - Forces the screen to sync to game's refresh rate instead of any windows that may be on top of it.
• Disables Windows Update.
• Disables notifications.
• Disables file indexing, if "Respect Device Power Mode Settings" is enabled in Search settings.
• Enables CPU scheduling optimizations for Ryzen CPUs.

Game Mode is enabled by default. If you had it disabled for some reason, you can enable it here.

Presentation Problems

Here's a comparison of three display modes you can use in this game. Situation is problematic mainly due to Vulkan and D3D9 using old presentation models.

This section is purely informative, just to let you know what options you have and what to expect from them.

5. Despite that disabled V-Sync unlocks the framerate, window itself is V-Synced, so you don't get any benefits.
6. While AMD enables FreeSync for Fullscreen Windowed BitBlt surfaces, Nvidia allows G-Sync to run with any window.
   This is problematic because refresh rate can get synchronized to wrong windows, framerate may break on other displays and display stutters may occur.
   Enabling it globally is a bad idea, because it disrupts normal desktop usage (e.g. screen can sync to sleeping windows).
   It's recommended to use Nvidia Profile Inspector to set G-Sync Application Mode to "Fullscreen and Windowed" in Fallout - New Vegas profile. This makes Windowed G-Sync run only when the game is running.
   Keep in mind that even with this method, this G-Sync implementation is still buggy - if you get any of the forementioned issues, disable it.
   

   Never enable Windowed G-Sync globally!

Translation Magic

DXVK is an open source Direct3D 9-11 to Vulkan translator project lead by Philip Rebohle (doitsujin) and Joshua Ashton. While created mainly for Linux, works unofficially on Windows.
In short, it allows you to run Fallout using the Vulkan API which has much lower draw call overhead than D3D9, which is one of the main performance limiting factors in this game.

Things to know

Due to the nature of DXVK and Vulkan itself, there are some things you should be aware of:

• DXVK improves performance in mainly draw call (CPU) bound scenarios (e.g. draw distance), and usually doesn't help much in GPU bound ones (e.g. resolution)

  • It is possible that DXVK won't change anything for you, or even make things worse

• You may experience increased stutter at the beginning of your playthrough due to shader compilation.

• DXVK's GPU compatibility varies between manufacturers

  • Nvidia GPU laptops must use the DXGI interop (see below).
    Using it on desktops is not required, but highly recommended for the most optimal experience

  • AMD GPUs must use the DXGI interop (see below), otherwise they will suffer from severe performance issues or fail to launch the game.
    Shader issues are more common on Windows compared to other GPUs (situation is completely reversed on Linux).
    

  • Intel GPUs from 6th Gen and newer can work provided you have newest drivers installed.
    On some iGPUs, DXVK is broken past the 1.10.1 version.
    

• DXVK can introduce or expose few visual issues or annoyances:

  • Transparency multisampling uses dithering - (Vulkan handles alpha to coverage differently than drivers)
  • Due to the nature of this effect, its quality improves alongside the level of MSAA used. It's recommended to use at least 4x MSAA.
  • If you are an AMD, RADV Linux user, you can disable this behavior by setting RADV_DEBUG=noatocdithering environment variable.
  • Blood decals can suffer from color overflow and turn white - Fixed by Blood Decal Flashing Fix

HDR-Mod

HDR-Mod is a DXVK mod made by Lilium (aka EndlesslyFlowering) and me with the intention of adding HDR functionality to D3D9 games. Effectively it does 2 major things:

• Allows to display the game in HDR (10 or 16 bit).

• Upgrades the precision with which the game calculates colors, greatly reducing banding - as long as you have a 10 bit display or better.

You can download this version of DXVK in the next step, in Optional Files.

Installation

1. Manually download the latest DXVK version from Nexus.

   GPUs lacking Vulkan 1.3 support or having issues with 2.0, must use the 1.10.3 version.

   Some older Intel iGPUs may need to use the 1.10.1 version.

2. Extract archive contents into your Fallout: New Vegas root folder.

3. If you have chosen the HDR version, download HDR Save Image Patch and install it with your mod manager.

Enabling Flip Model (DXVK with DXGI)

Nvidia and AMD drivers have ability to use DirectX to display Vulkan games allowing for Flip Model in Windowed mode, which has HDR and VRR support, and better latency.

---

Click on expanders below to see how to enable Flip Model for your GPU.

(Not) Pushing the Limits

Limiting framerate is very important for overall stability.
First and foremost, if you are using a good limiter, you'll be implementing correct framepacing, which is the most important thing for the overall feel of fluidity.
More advanced limiters can also reduce latency or power consumption (it's difficult to have both).

Recommended Setups

Recommended configurations based on selected display scenarios:

• V-Sync

  The "default" option - choose this if you don't have Variable Refresh Rate display or don't mind slight latency.
  • Framerate must be capped slightly below refresh rate to reduce latency.

  V-Sync on its own is NOT a limiter. Using it as one introduces a massive latency penalty.

• G-Sync | FreeSync

  Choose this if you have a Variable Refresh Rate display - it offers the best balance between latency and visual smoothness.
  • V-Sync must be enabled, in order to fully get rid of tearing.
  • Framerate must be capped below refresh rate, in order for VRR to not disengage and fallback to V-Sync, as this causes a very big increase in latency.

• No V-Sync

  Choose this if you want to reduce latency as much as possible, and don't mind tearing.
  • No special prerequisites.

  Due to Bethesda's oversight, the V-Sync toggle in the launcher doesn't work.
  To disable V-Sync, in FalloutCustom.ini set the following:

  [Display]
  iPresentInterval=0

  Disabling V-Sync through other means (Driver, DXVK) also works.

If you don't use, or not have VRR, it's best to limit your framerate to fractions of your refresh rate. (30 at 60hz, 72 at 144hz, etc.).
Having framerate capped to a value that's not a clean fraction of your refresh rate will cause microstuttering (For example 40 at 60hz).

RivaTuner Statistics Server

Riva Tuner Statistic Server by Unwinder is probably the most famous FPS Limiter and OSD software, thanks to its performance, compatibility and versatile On-Screen Display.

Installation and configuration

1. Install and launch RTSS. Open your System Tray (the triangle pointing upwards on the taskbar) and click on the RTSS icon to open it
2. Press green Add button and select FalloutNV.exe
3. Set Application Detection Level to Low
4. Enter your refresh rate here for automatic calculation of FPS limits. You can find your exact refresh rate here.
   CalculateDone! Due to physics issues, it's not recommended to go above 120 FPS.

   Even with New Vegas Tick Fix, game can still have issues with high framerates. It's recommended to cap your framerate to 120 FPS or below.

5. Set Framerate Limit to:
   • V-Sync

     (RefreshRate - 0.05)

   • VRR + V-Sync

     Any value between 48 and (RefreshRate * (1 - RefreshRate * 0.00028)).

     You should select a value that will match your average obtainable framerate in the game.

   • No V-Sync

     (RefreshRate)

6. Enter settings using Setup button and:
   • Enable Passive Waiting
   • Set framerate limiter to Front Edge Sync
7. Enable Start with Windows or launch RTSS everytime before you play

Your configuration should look similar to this:

Are these questions really frequent?

• I can't use DXVK, and I need to Alt-Tab!

  All you can do is download OneTweak and use the legacy Windowed mode.
  Remember to enable Windowed mode itself in FalloutCustom.ini!

  [Display]
  bFull Screen=0

• Fake Fullscreen, Borderless Windowed, Fullscreen Windowed, Windowed Fullscreen - is there any difference?

  No. All of these terms refer to the same thing - a borderless window that covers the whole screen. There's no official name for it, so people use different ways to describe it.

• Why is guide recommending using Windows' Game Mode? I heard that it's bad.

  Most, if not all Game Mode stigma comes around from its initial implementation in 2017.

  That version of Game Mode had two (now removed due to issues) features:

  • Resource prioritization - Game Mode would try to prioritize resources for the game, which led to issues with background applications, or breaking games themselves.
  • Flip Model upgrade for windowed games - Original implementation tried to upgrade selected D3D9 and D3D11 games, but often faced an issue where games would not exit software composition, leading to increased lag and worse performance.

  Modern Game Mode does not have these features, and instead focuses on generic Windows tweaks, like disabling background services (Windows Update, Search Indexing).
  Additionally, some vendors like AMD are using it to detect games and apply their own optimizations (CPU scheduling in AMD's case).

  Flip Model upgrade functionality has been moved into Windows itself, split between Fullscreen Optimizations (All Direct3D versions; Windows 10) and Windowed Optimizations (Direct3D 10 and 11; Windows 11).
  These features are enabled by default and don't suffer from the issues of the original Game Mode.

• Any way change brightness in Windowed Mode?

  Use ReShade or Dynavision to change the brightness.

• Do texture mods really have an impact on performance?

  In most cases, no. As long as you don't go over your VRAM budget and use NVTF's memory pool patch you'll be fine. If you happen to run out of VRAM, you'll get a massive performance degradation, due to graphics memory being spilled over into RAM.
  What is guaranteed from higher resolution textures is increase in their load time. This can translate into longer stutter periods on cell loads.

• You talk about HDR. I thought FNV already had it?

  HDR mentioned in game setting refers to HDR rendering, where game renders lighting passes in 16 bits, instead of 8. This leads to properly glowing lights thanks to the precision of using 65536 colors per channel instead of 256. (Glowing elements won't be clamped anymore, and will glow instead.)
  Due to the old age of the game, this data is later converted to 8 bit SDR (HDR in Windows was added in 2017!). Additionally, D3D9 obviously doesn't support HDR output in the first place, hence the need for the DXGI interop.

• DXVK is breaking HDR after exiting the game!

  Yes, unfortunately due to how FSE works, in addition to lack of native Windows support from DXVK, it doesn't properly handle the HDR API.
  If your GPU supports it, use DXVK with DXGI to resolve this issue.

• Is dgVoodoo 2 a viable alternative to DXVK?

  No. While it is true that you'd gain Windowed mode with Flip Model and HDR from it, in contrast to DXVK you are guaranteed to get lower perfomance due to the translation overhead.
  If you can handle the performance loss, sure go ahead.

• During ReShade installation, which API should I choose if I use DXVK?

  Vulkan.

The End?

Congratulations! You've made it through! I hope this guide has helped you making Fallout: New Vegas a smoother experience.
If you have any issues, questions, critiques or recommendations hit us up on Discord - wall_sogb and Ungeziefi.
You can also find us on ModdingLinked, xNVSE, Tale of Two Wastelands servers.

I recommend checking this guide from time to time - We're not done yet.

If you found this guide helpful, share it with others or support me on Ko-Fi or Patreon

Things worth reading

Here are some links to stuff that I recommend checking out:

• New Vegas Visual Renewal - nice and easy to follow graphics guide by Salamand3r that actually doesn't break your game for a nice change of pace.
• PCGamingWiki - Great website, contains really helpful info about games, patches, fixes and other PC gaming related stuff.
• BlurBusters - Amazing website by Mark Rejhon focused on displays, latency and image quality. Really worth checking it out if you are a geek for these things.
• HDR Den - Discord server dedicated to HDR enthusiasts and developers. If you want to learn more about HDR, this is the place to go.

Credits

This is the part where I'd like to thank people who have helped me in whatever way to make this guide possible.

• Whole xNVSE server for being a great community. Especially:
  • Ungeziefi for testing and helping with benchmarks.
  • c6 for fixing the some engine functions so my testing could be easier.
  • LOC (aka ItsMeJesusHChrist) for making the awesome logo for the guide.
  • Nice try karut, but you are not getting credited.
• The Special K server for being a superb community with a lot of knowledgeable people. This guide would literally not exist without them.
• Glaceon575 for helping with benchmarks and providing screenshots for AMD GPUs.
• You.

Changelog

Changes are documented in the commit history.