Haven't run into any areas that drop below 60 fps yet even at Ultra settings with the exception of loading slowdown. This IS an AMD game after all.
With vsync off my framerate is over 100 most of the time. Though you're right about the Ultra shadows not looking any different than very high.
Core i7 5820K hexa-core CPU || 8 GBs 2400 MHz DDR4 || Nvidia GeForce GTX 970 || Dual 128 GB SSDs