It's... substantially worse.
I have a GTX 590 and I'm capping at 30fps, maxing settings, and injecting SMAA.
I mean, the SMAA is taking up some frames, but not THAT much. Maybe like 10.
Eh, whatever, probably time to reformat. If you can hit 1080/60 on a GTX 660... then Jesus, my shit is fucked up. (590 > 680, for comparison)
At 1920x1200 windowed fullscreen on nearly-max-settings using native AA I easily get 60FPS while running dual monitors unless I'm in a crowd (then I drop to about 30, but it's a smooth 30 not a chuggy 30). Instances, party combat, soloing, all 60FPS easily. Aetheryte hubs/town crowds, FATEs, yeah, I drop to like 30. 4GB 670GTX. The max-res shadows are a killer in crowds, I've noticed--setting them to mid res is a big FPS boost in crowds, but I leave them on max since the FPS drop in crowds isn't bad and I like the sharp shadows. Even in crowds ARR is nothing like TERA bad lol.