I realized that when this ground texture mod is applied, fps is reduced to 30+ from 40+ when close to the ground. I couldn't bear it, so I deactivated the mod for now... which is a shame. I liked this mod a lot.
I am using Gigabyte 680 OC 2G, i5 3570K stock, 16G of ram and a Corsair SSD 240G.
I suspect it is because of the limited amount of vram. But I am not sure.
Do any of you notice that?