A user by the name of izy on the TechPowerUp forums posted details on a DX12 to Vulkan mod that supposedly boosts performance on Nvidia's GTX 1080 Ti by 50% in Alan Wake 2. This particular mod leverages the DX12 to Vulkan work already done for Linux, except it can potentially work on Windows with older GPUs.
According to izy, the mod has been tested by multiple TechPowerUp forum users with a plethora of older GeForce products like the GTX 1070, GTX 1080, and GTX 1080 Ti. According to one forum user, the izy's DX12 to Vulkan mod was able to boost frame rates by 50% in Alan Wake 2, from 22 FPS up to 37 FPS using the low-quality preset.
However, the mod isn't without its faults. izy affirms that the mod won't perform miracles on every system, and revealed that the mod didn't work for a lot of people, including both Nvidia-powered rigs and AMD-powered systems. Our resident GPU reviewer, Jarred Walton, tried to get the mod running on his test setup, but like some others reported, he only achieved a black screen followed by an immediate crash to the desktop. (For reference: Overlays were disabled, VC runtimes installed, rebooted the PC, etc. It may be a driver conflict, but that's enough effort for now.)
Regarding Alan Wake 2 performance, higher performance may not be a universal win for older GPUs. There may be differences in post-processing quality, some users reported significant stuttering, and other issues may arise. But 30+ fps even with some stuttering would be better than the current 22 fps the 1080 Ti gets (still with stuttering).
The Vulkan translation mod is another potential use case for Vulkan translation technologies outside of the Linux ecosystem. In the future, DX12 to Vulkan translation techniques could be a legitimate way to allow older Windows operating systems (Windows 8.1 and Windows 7) and older GPUs to attempt to run the latest DX12 AAA titles. Whether performance would be acceptable will of course vary by game.
If you're hoping to play Alan Wake 2 on a GPU that doesn't support mesh shaders, give the mod a shot. Some have reported getting it working with AMD cards as well, though FPS improvements aren't necessarily at the same level as the 1080 Ti.
