This game uses nvapi so it needs a workaround to get best performance on Nvidia cards. This workaround was added to DXVK git, but in the mean time you can create dxvk.conf in (steam library location)/steamapps/common/DRAGON QUEST XI/Game/Binaries/Win64 with the following:
dxgi.customDeviceId = E366
dxgi.customVendorId = 1002

Thx im waiting for new proton update and retry this game :D
Actually work great but in open world is not laggy but fps down :(.
New proton update to make better support would be great !

Is this commit : https://github.com/doitsujin/dxvk/commit/60796a814387392234a65340605805381fd90264

It's the same idea as in that commit, just done by default.

On another note, the game seems to exhibit several second freezes with AMD cards (RX 550 and Vega 56 tested). Could be shader compilation stuttering but it appears to be a lot more severe than with Nvidia cards and seems to persist rather than go away eventually. Will have to test further.

Nvidia's shader compiler is faster than that of RADV. Also, make sure that your Mesa is built in release mode with assertions disabled, it you built it yourself.

Yeah, it was just shader compilation. I hadn't realised how much slower RADV was in that respect. I did briefly try the async compiler (outside of Proton) although it didn't seem to help dramatically.

This is apparently an issue that appeared with a change in the way Steam manages non-Steam-controller gamepad devices.

Funnily enough, I did test the SC and the issue was still present.

Anyway, thanks to /u/Kaigan on Reddit that gave me a fix for this.

Disabling non-SC configuration management support (Force Off) fixed the problem for me and apparently on Monster Hunter too for people that were having the same problem.

Can no longer launch this game. Was working perfectly but now it says "the server is not reachable". If I click 'Retry' it just pops back up with the same message. If I click 'Next' then it brings another dialogue up however it's visible for less then a second before it closes. I managed to screen cap the dialogue and it is showing a website I need to visit but there is also supposed to be a code shown on the dialogue to paste on to the website to verify - this is not present and the length of time the box stays open would make it incredibly difficult to copy or paste anything.

Edit: Fixed with symlinking "/usr/lib//libgnutls.so.30.14.11" to "$HOME/.steam/steam/steamapps/common/Proton 3.7/dist/lib/libgnutls.so.26

(This is on manjaro)

I've had near flawless performance on my setup save for garbled sound. Sometimes relaunching the game gets rid of it. Unfortunately I dont guess this is quite yet ready for whitelisting. For reference im on proton3.7-7 beta.

I've had near flawless performance on my setup save for garbled sound. Sometimes relaunching the game gets rid of it. Unfortunately I dont guess this is quite yet ready for whitelisting. For reference im on proton3.7-7 beta.

I'm also getting garbled sound, but it's been 100% of the time for me. I'm on an AMD platform though so I'm not sure it it's related since I hear most people with Nvidia are fine.

Specs:

Distro:
    Antergos

Processor Information:
    CPU Vendor:  AuthenticAMD
    CPU Brand:  AMD Ryzen 5 2400G with Radeon Vega Graphics    
    CPU Family:  0x17
    CPU Model:  0x11
    CPU Stepping:  0x0
    CPU Type:  0x0
    Speed:  3530 Mhz
    8 logical processors
    4 physical processors

Operating System Version:
    Linux 4.x (64 bit)
    Kernel Name:  Linux
    Kernel Version:  4.18.12-arch1-1-ARCH
    X Server Vendor:  The X.Org Foundation
    X Server Release:  12001000
    X Window Manager:  Mutter (Muffin)
    Steam Runtime Version:  steam-runtime-beta-release_2018-09-03

Video Card:
    Driver:  X.Org Radeon RX 580 Series (POLARIS10, DRM 3.26.0, 4.18.12-arch1-1-ARCH, LLVM 7.0.0)
    Driver Version:  4.4 (Compatibility Profile) Mesa 18.2.2
    OpenGL Version: 4.4
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 59 Hz
    VendorID:  0x1002
    DeviceID:  0x67df
    Revision Not Detected
    Number of Monitors:  2
    Number of Logical Video Cards:  1
    Primary Display Resolution:  2560 x 1080
    Desktop Resolution: 4480 x 1200
    Primary Display Size: 31.42" x 13.15" (34.06" diag)
                                            79.8cm x 33.4cm (86.5cm diag)
    Primary VRAM: 4096 MB

Sound card:
    Audio device: ATI R6xx HDMI

Memory:
    RAM:  16034 Mb

Miscellaneous:
    UI Language:  English
    LANG:  en_US.UTF-8
    Total Hard Disk Space Available:  236782 Mb
    Largest Free Hard Disk Block:  71350 Mb
    VR Headset: None detected    

For those with pulseaudio and are having garbled audio issues try putting this in your launch parameters and see what it does for you: PULSE_LATENCY_MSEC=120 %COMMAND%

I'll be out of town this weekend, but I'll give it a try Sunday night if I can remember.

I added the launch option for Dragon Quest that was recommended above and played it for roughly 5 hours.

To provide a little bit more detail about my issue in the past. Typically the audio works great for about 45 minutes before starting to garble. It also would get worse if I turned my headset on or off. The garbling distorted the sound quite a bit to where I would quit the game and relaunch it to clear it up. (Its pretty immersion breaking when the audio messes up like that.)

After adding that launch option The audio did not distort after 45 minutes like it did previously. I tried toggling my headset on and off as well with no issues. I will say though that after about 4 hours it started to garble again but nowhere near as bad. Overall I would say it greatly improves the experience even if it doesnt iron it out 100%.

Thanks for the tip!

@teldon I've only just started the game, but the audio sounds perfect now. I'll continue to play throughout the week and will report back if I have any other issues. Great find!

Alright it's been two weeks and I've put 12 hours into the game with no issues after adding PULSE_LATENCY_MSEC=120 %COMMAND% to my launch options.

Admittedly, none of my sessions have gone over two hours though so I can't say if this solution works for long periods of time.

For me, the game does no longer launch at all, neither on my desktop (nvidia) nor on my steam deck - even though it's verified. (The Digital Edition Of Light, the Definitive Edition seems to work fine). It shows the little pre-launch popup, then goes to black screen, shows loading... and the two steam popups for the overlay and the gamepad config and then it just crashes.

steam.log
steam-742120.log

Okay i actually (by accident) just found a solution for this. It was a corrupted save game. Check the games comminuty discussions (e.g. https://steamcommunity.com/app/742120/discussions/1/1638661595043442217/ ) on how to fix this properly, i just disabled cloud sync, nuked my compatdata folder for the game, launched it, then reenabled cloud sync (THIS WOULD LOOSE YOU ALL YOUR SAVEGAMES!!!).