It is impossible to give you a number, because there are so many factors.
What resolution are you going to be playing at?
How much memory do you have?
Did you overclock anything?
Also, you could probably get 60FPS easy if you did low-medium settings at 1366x768 or 1600x900, but if you want to do high-ultra at 1080p you would be lucky to get 15-20FPS...
8gb 1866mhz ram.