Assuming you're at 1080p, you can max it, but it will look like a slide show of 25-35fps. So if you really want to max it at 50+ fps you'll need another 680 or get a 690.
But honestly if you turn down a couple graphic settings one notch and use SMAA 2x, you'll be fine.
You can run C3 on Very High with those setting and abit of AA (2x SMAA) but you won't be running at 60FPS, and you're frames will tank on the grass level to sub 30FPS in some parts,
You might get away with High @ 60FPS but not always.