Did a test on my PC with the exact settings you requested, and got low 40s generally. I'm sure I'm CPU bound to an extent though. Hairworks is just not worth it imo. I usually play with a ReShade Preset, modded LOD past ultra settings, HD texture pack, SMAA etc, and I get over 50+ FPS in the same area at 6pm, without Hairworks. It looks much prettier.