Yes. Your FPS and refresh rate are different, however they are still related.
If you get 100FPS, but your LCD can "only" refresh at 60Hz (60Hz = 60 refreshes a second), you will still only see "60FPS".
However those FPS still matter though, for example if you see 60FPS on a 60Hz LCD, it will look smooth, but a 100FPS on a 60Hz will probably look slightly smoother.
Some people can detect differences between 30/60/120FPS. So you have to decide if you want a 120Hz panel or not. If you do get a 120Hz panel you might want to get a 680, as it can give more FPS than the 670.
By the way my explanation is a simple one. It's much deeper than that, i'm just telling you how it works in my own words. If any other members want to flog me for bad information, or if i'm wrong about something, feel free!
Heres some good informatio:
http://www.ehow.com/about_5187855_difference-120hz-hd-lcd-tvs_.html