Cyberdimension Neptunia: 4 Goddesses Online (632350)

System Information

• OS: Ubuntu 18.04 64-bit
• GPU: Nvidia GTX 1080 Founders Edition
• Driver/LLVM version: NVIDIA 410.57
• Kernel version: 4.15.0-36-generic
• Link to full system information report as Gist:
• Proton version: 3.16-3 Beta

I confirm:

• that I haven't found an existing compatibility report for this game.
• that I have checked whether there are updates for my system available.

steam-632350.log

Symptoms

When entering Oneiro Corridor, Arodie Cavern, or Tetyu Temple, the fps drops down to single digits making the game unplayable.

Reproduction

1. Start the game
2. Play until you unlock one of those 3 areas (or load a save that has those areas unlocked)
3. Enter one of those 3 areas
4. The game will have low fps when looking towards the rest of the area.

I've attached my zipped save file in case you find it useful. The save was located in C:\Users<username>\AppData\Local\CyberdimensionNeptunia4GoddessesOnline\Saved\SaveGames\

I don't know where the equivalent would be on linux, so I grabbed the save from my backup of my windows partition.

save.zip

From my brief look at the log file, it appears to be because nvapi64.dll fails to load.

Start by reproducing the slowdown in Oneiro Corridor, Arodie Cavern, or Tetyu Temple using the attached save.zip and Proton 3.16-3 Beta. Inspect steam-632350.log, especially the reported nvapi64.dll load failure, alongside the listed Ubuntu, kernel, GPU, and driver details. Done means those areas no longer drop to single-digit FPS.