Help with nvidia gtx 550 ti

Just build my first pc yesterday, installed the video and mobo and monitor drivers.. Trying to get my viewsonic fuhzion 120hz 3d monitor to run 120hz but when I checked 120hz it created horrible blurryness and tearing on the screen then began flickering -- I don't think it's the cable, video card, or monitor -- I just think there's a little tweak I'm forgetting to get it to work -- any help? Can't get it past 60 hz