chanDepends on the resolution and SSAO scales. These 2 are VRAM suckers.
If I'm 'reasonable' (1620p max and 0.806 scales), I'm averaging from 45 to 55 FPS vsync on, thanx to my rig. 2x690 is a quad SLI, and 4GB VRAM, so it can take almost (almost) everything you throw at it.
On the 2x580 rig (3GB VRAM), almost same results @1080p, from 35 to 45-50. @1440p, I'm already loosing 5 to 10 FPS in heavily wooded zones (25 to 30 max).
If you refer to my shots above, these are 4K (3840x2160) with 1.41 (doubled) scales. My FPS were on the low 10 to 15 here
Thus said, my iMinGrassSize is 20, and I'm using Lush Grass + Glorious Grass, upon Skyrim Flora Overhaul Summer Edition with Trees in HD textures (4096).
DOF is always on, my modifications on gpc's initial code, set to Q5.
goddavidLooks good

Custom preset ?