i have mp2800, 1G and 9800xt and it struggles with physics min, effects min, everything else mid, textures max 2xAA and 16xAF. careful settings selection gave me usable performance.
once i turned off shadows (not a huge problem for me, i don't really notice/care) i got a massive boost and now i can max everything and get decent frame rates.
screens coming... nothing too spoilerish but look away now if you don't want to see
this one give an idea of what it looks like entering slowmo. it's soooo much better when your playing, the physics, explosions and dust everywhere make things seems very hectic. notice the blood exiting the nearest dudes head, the bullet trails and the dust and sparks at the back left from nailing the guy on the floor
i'll try and get a 'nade in action shot later as the clouds kicked up are impressive, but it's hard to hit f8 while under fire