This benchmark was taken right after the launch of BF4http://tinyurl.com/p83x34p
54fps at reference speed, at Ultra 1920x1200 (Singleplayer timedemo)
With an overclocked card and 4GB vram, it will be better.
At the slightly lower resolution of 1920x1080, it will be better.
With updated and optimized graphic drivers, it will be better.
With game updates and bug/performance fixes, it will be better.
In multiplayer however, performance will take a hit. The extra vram will be beneficial as whole maps and many more objects will be loaded.