Saphire 5570 display port Woes

I have Saphire Radeon HD5570 installed on my i3 system. I am having a hard time, ie impossible to get the display port to output the native resolution to my monitor. Which is 1680 x 1050. It will go as high as 1600 x 1200, the previous menu choice 1600 x 900. under display properties in the catalyst control center for the monitor i'm trying to affect. The card's vga and dvi can both get to the native resolution of 1680 x 1050, just not the display port.

I was going to enjoy a few eyefinity games with lower graphic settings and live with a little less frame rates.

Has anyone else had this issue? I am using eyefinity mode in 3 monitors now 1680 x 1050 now just fine, but it does make these landscape models have a black bar at the sides wasting possibly resolution. And even when I only plug in the one monitor to the displayport it cannot output 1680 x 1050.

I am just wondering if I have a bad card or is it a short coming of that model that is being hidden in technical jargon of what the possibility of resolution display port can put out vs what that model card can actually do via display port.

Or if there is anyway in the software to make it work with my desired resolution.