Hm, I guess you have also already tried raising the audio delay?
Other than that I fear I don't know what else could help.
Is this game too demanding?
Im using 60fps code (umbrella chronicles crash at launch with the 60fps code) and on a i5 and GT1030 cant reach 60FPS at 2x IR. It stays around 50FPS. In vulkan, on other renders is even worst.