
LD_PRELOAD="" %command%
After 30 minutes of playing, the game drops to extremely low FPS without launch options.
Add "LD_PRELOAD="" %command%" launch option.

Works most of the time
The mouse could escape the window if moved fast enough.
I tried launch options, but those just caused more issues with my setup. At one point it always failed to close when I tried to close it from within the game and I had to close it through steam but that seems to be fixed. It crashes about as much as a bethesda game does.

Hardware requirement is higher than Windows counterpart. Certain mods and reduced graphical settings can help improve performance.
Screen height or positon can be borked. Manual edit on Fallout76Prefs.ini might be required.
Power Armor / Quickboy will be missaligned, appearing out of the screen. Add these to Fallout76Custom.ini:
[Display]
fDefault1stPersonFOV=100.0
fDefaultFOV=100.0

The first multiplayer Fallout game and it runs pretty well on Linux, barring some minor issues.
Game runs okay without tinkering, but to reach a comfortable 60fps you need to lower the settings down in the game's settings and use text editor to edit the ini file.
Lower TDP to 12W and set the in-game graphics to default Low to get around 40 - 50 fps. Performance will definitely tank in events or raids where are dozens of players and entities.
Subtitles are too small for the Steam Deck screen. Small texts for quests also going to clutter the top right of the screen if you decide to track all quests available.
Exiting the game through the main menu simply freezes the game. Need to close the game manually through the Steam overlay menu.
Fallout 76 runs pretty well on Steam Deck by default without any tinkering, but for the most optimal performance some tinkering needed. Mostly changing the configuration ini files would be enough but you can go beyond by installing mods that further improves the performance and/or quality of lifes. The game initally suffers from terrible bugs on launch and to be honest the game still has plenty of bugs, one can argue that turning a 20 year old Creation engine into an MMO framework is no easy feat. And in the end of the day this is still a solid Fallout game.

LD_PRELOAD="" %command%
After 30 minutes of playing, the game drops to extremely low FPS.
Game is unplayable after running for about 30 minutes.
This game now absolutely needs a launch option of LD_PRELOAD="" to avoid the problem of the game dropping to unplayable FPS after 30 minutes of running. This started happening a couple updates ago, but Gleaming Depths has made it worse.

DXVK_FRAME_RATE=90 gamemoderun %command%
The game will randomly run at 10 FPS and won't stop until I restart the game. This happens at least once every 30 minutes but usually more often.
I notice this game crashing every third time I play. It always takes a couple of hours of playing to occur.
I have tried various fixes to get this game to work. Setting graphics to low, dropping resolution to 720p from 1440p, messing with the .ini manually, updating gamemode to the latest version, giving the game the highest priority within System Monitor, installing different graphics driver versions, and installing various Windows components with protontricks. Nothing I have done has been able to fix the performance issues I've been experiencing. I first noticed this when Bethesda released a big shader update, so I'm chalking these issues up to typical Bethesda bugs.
If you want to play this game, I recommend dual-booting Windows. This game runs better on Windows than it ever did on Linux.

Runs great
Perfect performance on Linux. The only issue is that it hangs when exiting using the game menu. You just have to force close it from steam.
Works perfectly.
works well

Run the game at least once > run protontricks > default wineprefix > install Windows component > choose latest faudio. It'll silently update stuff in the background; wait for the protontricks window to come up again, close them, then run FO76 again.
Audio non-functional without protontricks, see that section
run the game at least once > run protontricks > default wineprefix > install Windows component > choose latest faudio. It'll silently update stuff in the background; wait for the protontricks window to come up again, close them, then run FO76 again.
audio missing at first; see protontricks notes
In borderless full screen, using alt-tab can temporarily freeze FO76 in the background. When regaining focus, the "back log" of frames will rush back at high speed. This problem seems to be easily avoided simply by mouse-hovering over the FO76 window while it's in the background.
Overall performance seemed equal or slightly less than my Windows setup.
For Steam flatpak version, migrate your old settings and in-game snapshots from:
(Windows drive)/Documents and Settings/(Windows user name)/Documents/My Games/Fallout 76/
copy into:
/home/(username)/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/compatdata/1151340/pfx/drive_c/users/steamuser/Documents/My Games/Fallout 76/

Running no forced Steam compatibility option, the game would run fine aside from being capped at 40fps. I had to use a custom Fallout76.ini and Fallout76Prefs.ini settings file to get it to work with an uncapped framerate and no other issues. I made a steam guide that includes my custom .ini settings: https://steamcommunity.com/sharedfiles/filedetails/?id=3361856512
Without custom .ini settings, the game ran at a locked 40fps.

gamemoderun GDK_BACKEND=wayland steam steam://rungameid/1151340
установил gamemode и lib32-gamemode, вся система работает на X11 ну а сама игра запускается на wyland
Пришлось снизить графику с высокой на среднюю, но фпс получился вполне играбильный(60 с резкими просадками до 45), хотя ранее подобный фпс я получал на высоких(на винде10)

Fog sometimes causes artifacts/smearing
Low framerate and stuttering. Might be the same on windows.
Trying to do things at the menu before the Atom Shop has loaded seems to cause CTD
Game does not start when running the anthraxx/linux-hardened kernel

Unlocked FPS within ini file to go over 60fps
Worse than windows, but perfectly playable
Exiting the game requires you to kill the process, as it hangs, other than that the game is pretty much equivalent to the windows version

gamemoderun %command%
Not much work and working perfectly.

I think that you should disable split lock mitigate if you'd have a shot at actually playing this game
ipresentinterval=0
Huge Micro-Stutters
sudo sysctl kernel.split_lock_mitigate=0 is what i put in terminal to disable split lock mitigation to solve any issue I had with frame times and micro-stutters and it worked flawlessly after

The game started crashing on startup due to me changeing the fullscreen option to borderless. I had to deleat my INI file to make it stop. I did this using proton tricks to launch explorer, then navagated to C:\users\steamuser\Documents\My Games\Fallout 76 and deleated the two .ini files there. there are outher ways to deleat them without using proton tricks, but this is how I did it.
DO NOT GO BORDERLESS! It will cause crashes.
The game will hang when exiting. It must be closed by force.
PROTON_USE_WINED3D=1 %command%
Game freezes when exiting, requires manually killing process.
After all these years, game is still buggy as heck, but no fault of Proton.
Fallout 76 servers occasionally go down or have high latency, but no fault of Proton.

Game just worked out of the box. I'm using KDE running on X11 not Wayland.

gamemoderun %command%
Game freezes when quitting to desktop. Exit to menu and then force quit the game to close it

Use BTRFS as the file system and this game will launch!

gamemoderun DXVK_FRAME_RATE=100 %command%
Game doesn't close cleanly when exiting, it just hangs until you terminate the process. I recommend closing it with the good old Alt+F4 (the window doesn't hang this way) and then terminate it via steam.
Installed the game through steam and worked out of the box, but I wanted to use some mods (TZMap, some glowing stuff mods, etc).
So, how did I managed to get mods to work with proton:
First I tried installing MO2 with "Mod Organizer 2 Linux Installer" (https://github.com/rockerbacon/modorganizer2-linux-installer ) and an unofficial plugin for Fallout 76 on MO2 (https://www.nexusmods.com/fallout76/mods/2090 ) but the MO2 linux installer doesn't support Fallout 76 at the moment. I tried to modify the .sh scripts myself and add support for Fallout 76 (it worked partially, letting me install and open MO2 and launch the game with mods applied, but then the game just refused to sign in and kept asking for my username and pass everytime, just to give an error when provided).
Then, I gave up on MO2 and simply downloaded Fallout 76 Quick Configuration (https://github.com/FelisDiligens/Fallout76-QuickConfiguration ), installed it in a folder inside my Fallout 76 install folder and added it as a Non-Steam app with the following launch option: "STEAM_COMPAT_DATA_PATH="/home/username/Games/SteamLibrary/steamapps/compatdata/1151340/" %command%" (this is where I have my steam library) so it uses the same wine prefix as Fallout 76 and is able to find its ini files. Then just installed my usual mods and applied. Launched the game normally through Steam and voilà! Working fine with mods and the same performance I got on Windows with the same machine.
If you prefer, I suppose you could just manually move your .ba2 mods to Fallout76/Data folder and add the name of each mod to the Fallout76Custom.ini and it should work, but I wanted some kind of mod manager.

PROTON_USE_WINED3D=1 %command%
Not sure how to put this but textures stay where they were on your screen as you move the camera around.
Crashes in fullscreen mode, but borderless windowed works
Constant crashes within 2-3 minutes of starting the game.
Not worth the effort

Stuttering, Flashing and low fps before tinkering. Now runs better than windows at ultra ,constant 60fps with no stutter or screen flashing
DXVK_FILTER_DEVICE_NAME="NVIDIA GeForce RTX 3050 Laptop GPU" gamemoderun DXVK_FRAME_RATE=60 %command%
Crash upon exiting the game
Runs amazing with added launch options and proton GE 9-10, change NVIDIA GeForce RTX 3050 Laptop GPU to your GPU

Unplayable due to stuttery framerate
Framerate stutters even on lowest graphics settings
Crashes on exiting game, have to end process

Stuttering framerate
Crashes on exiting game

DXVK_FILTER_DEVICE_NAME="NVIDIA GeForce RTX 3050 Ti Laptop GPU" gamemoderun DXVK_FRAME_RATE=60 %command%
On the first startup the game is set to 1920x800, i didn't really have any problems with fullscreen but it is still recommended to switch to borderless.
Micro stuttering. Micro stuttering and micro stuttering. The only solution to this problem is to get used to it.
The game does not shut down properly
if you are running a system with an iGPU enabled you WILL NEED this launch option: DXVK_FILTER_DEVICE_NAME="Your Actual GPU here" %command% , otherwise the game will run at 15-20fps.
I recommend limiting fps to 60 because the trash engine this game uses is not designed to run at more than 60 frames.
The only real difference between running this game on windows is stuttering, it is unpleasant at best and under some circumstances its just borderline unplayable.
Looks like trash, runs like trash. Certified Bethesda classic.

gamemoderun %command%
User error. Updated Nvidia drivers and didn't restart the system.
All I use is [gamemoderun %command%] and it runs no problem. Just make sure everything is updated and to restart your system after or you might spend 30 mins irritated like I did.

Overall solid experience, but Wayland specific multi monitor bugs were a real pain to fix
gamescope -e gamemoderun -w 2560 -h 1440 -W 2560 -H 1440 -f --force-grab-cursor -- %command%
Mouse would leave the window if moved too fast.
Always hangs when trying to exit which leaves the process and wineserver runnning in the background. To start the game again (with gamescope), either restarting Steam or killing Wineserver is mandatory.
Runs fine with gamescope and the additional parameters, but the process not terminating succesfully especially when using gamescope is also very annoying.

Audio was very messed up. Odd Clicking, some ambient sounds. no music. This was fixed with GE Proton.
The game will not shut down normally. I have to end it from my steam library.
For me it NEEDED Custom Proton to be playable. With Custom Proton the only niggle is not shutting down cleanly. Definitely a safe buy, especially if you get it on sale

gamemoderun gamescope -w 2560 -h 1440 -W 2560 -H 1440 -f -- %command%
Wayland specific bug made the mouse not lock ingame and occasionally leaves the window.
Closing the game without Alt + F4 hangs the process

other than fullscreen not completely functioning the game runs at a solid 60fps on ultra settings
fullscreen did not fill up the entire screen, however windowed borderless does the job

Ran it with SteamTinkerLaunch to be able to install Vortex Mod Manager and played with mods that way. No problems with that either.

Yes and No. It will work, but you need to throw a lot of hardware at the game to make it feel good. 4070 in 1080p dont feel good.
Mouse is going outside screen. Can be fixed in winecfg with dedicated gpu. Can not be fixed on hybrid gpu.
Does not run well compared to windows. Tested proton GE, TKG, Experimental and native. Tested also Cachyos-proton, no success.
Gpu is not utiliezed as it should either. Common to see 45-65% at max, even you cant maintain 60 fps, while looking at gpu sits around 50%. Seen some places that it can start to stutter and crash in linux. I have tested pretty much every known settings and launch options. This is tested on 2 systems, one desktop and a laptop. Same resaults. Where one system Is intel I7 /nvidia Rtx 4070, then on Amd 7800x3d / Rtx 4090.
Difference is night and day from linux and windows atm.
Can not exit game, when "quit to desktop". Have to tab out to either process kill, or stop game in steam.
MANGOHUD=1 MANGOHUD_CONFIG=fps_limit=60 %command% - Set to your minitors Hz [Display] iPresentInterval = 0
Can help with keyboard stop responding towards movement, and should in theory help with using more of the gpu, where i dont see it in linux, but better effect in windows.
This game has a few to many issues as it is

gamemoderun gamescope -w 1920 -h 1080 -W 1920 -H 1080 -f -- %command%
Mouse can leave the game window unless you lock it with gamescope, also game crashes on close but thats not an issue since your stopping play

Basically no sounds, performance was ok, around 60 to 80 fps in the outerworld (at least outside of vault 76) but no sounds is a killer
PROTON_NO_FSYNC=1 WINE_FULLSCREEN_FSR=1 WINEDLLOVERRIDES="xaudio2_7=n,b" %command% WINEDLLOVERRIDES="xaudio2_7=n,b" mangohud %command% WINEDLLOVERRIDES="xaudio2_7=n,b" PULSE_LATENCY_MSEC=90 PROTON_LOG=1 %command% WINEDLLOVERRIDES="xaudio2_7=n,b" PULSE_LATENCY_MSEC=90 %command%
Basically all audio is missing, the videos do have sound, like the please standby and the start of story video, but the game itself has basically no audio. The menu has absolutely no audio at all and the game itself only has like miscellaneous sounds like background buzz sounds, holotapes, birds things like that and guns. But there are no voices, no steps, jumps, doors opening, radio, nothing else sounds. Tried various proton, experimental proton ge, winetricks nothing worked.