New Built Computer Receiving some lag in games.

Hey guys,
I recently built a new computer with the specs listed below
GPU: GTX 570 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
RAM: 16GB DDR3 2400 http://www.newegg.com/Product/Product.aspx?Item=N82E168...(Desktop+Memory)-_-G.SKILL-_-20231587
The game's also running off an SSD.
Monitor plugged in via HDMI: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

I paid around 1.7k for it figuring I shouldn't have any issues playing high end games with it on full settings. I'm playing Assassins Creed Revelations with the following settings and I'm receiving some weird FPS drops.
Resolution: 1920 1080 59HZ
Multisampling: 8x
Vsync: on
Environment Quality: MAX
Texture Quality: Max
Shadow Quality: Max
Relfection Quality: High (MAX)
Character Quality: Max
Post-Effects: On

Now right now I'm taking a guess that this is because either my GPU (maybe I should get a second for dual booting GPU) or because my monitor.

Please let me know if you guys can help me out here I wasn't too sure if I posted in the right place or not but any help would be nice, thanks.