Dual Monitor lower fps?

ok guys i have a gtx 550 ti and i will be buying a new 1080p monitor for gaming, i have a standard tv already on pc mode. So by using the 1080p monitor for gaming and use the other monitor just to have a google tab open will my fps be lower in game?

As far as my experience with dual monitors goes, I haven't experienced any lower FPS using 2 monitors. Only if you'd run a game on both monitors with eyefinity or something wich my knowledge is very limited about.

when i'm playing farcry 3 and i have my tv as extended desktop i experience a loss of fps 10 or so

then again i have a 4650 so it might be because i have a old gpu

What matters is the resolution of the game window - if it stays the same and the extra screen is used for other stuff there should be no difference in fps.

thanks guys