Sword Art Online: Fatal Bullet (626690)

Very low performance (~15 FPS - ~20 FPS instead of 60 FPS) happens sometimes, depends of view orientation in game. In some cases game tries to load nvapi64.dll continuously which is missing in Proton:

13516.763:0026:006b:trace:module:get_load_order looking for L"C:\\windows\\system32\\nvapi64.dll"
13516.763:0026:006b:trace:module:get_load_order got hardcoded default for L"nvapi64.dll"
13516.763:0026:006b:trace:module:load_builtin_dll Trying built-in L"nvapi64.dll"
13516.763:0026:006b:warn:module:load_builtin_dll cannot open .so lib for builtin L"nvapi64.dll": /mnt/hdd/steamapps/common/Proton 3.7 Beta/dist/lib/wine/nvapi64.dll.so: nie można otworzyć pliku obiektu dzielonego: Nie ma takiego pliku ani katalogu
13516.763:0026:006b:warn:module:load_dll Failed to load module L"C:\\windows\\system32\\nvapi64.dll"; status=c0000135
13516.763:0026:006b:trace:module:load_dll looking for L"C:\\windows\\system32\\nvapi64.dll" in L"Z:\\mnt\\hdd\\steamapps\\common\\SWORD ART ONLINE FATAL BULLET\\SAOFB\\Binaries\\Win64;C:\\Program Files (x86)\\Steam;C:\\windows\\system32;C:\\windows\\system;C:\\windows;C:\\windows\\system32;C:\\windows;C:\\windows\\system32\\wbem"

Coping required DLL from system wine-staging /usr/lib/wine/nvapi64.dll.so into /mnt/hdd/steamapps/common/Proton 3.7 Beta/dist/lib64/wine mostly resolves the problem. Performance on my PC seems to be good, but the library nvapi64.dll logs errors continuously:

14130.222:0026:0074:err:nvapi:NvAPI_D3D11_SetDepthBoundsTest Failed to get wined3d device handle!

OS: Manjaro Unstable (kernel 3.18.5)
GPU: GTX 1080 (driver version 396.54)
Proton: 3.7-5

Start by reproducing the low-performance behavior for Sword Art Online: Fatal Bullet with Proton 3.7-5 and inspect the repeated nvapi64.dll load and NvAPI_D3D11_SetDepthBoundsTest errors. Compare behavior with the reported wine-staging nvapi64.dll.so placement. Done means the game no longer repeatedly loads the missing library and performance is improved without continuous nvapi errors.