AMD 7950 GPU - Dual monitor - 27" and 24" same resolution?

Hey guys, I just got my 2nd monitor which is 27" instead of my old 24".
When I hooked my new monitor up via HDMI it had the same resolution as my other 24", with black borders around the screen.
Any way to make the 27" inch have higher resolution? I just looked it up, and I know that HDMI can have up to 2560x1600, and the same with my GPU which also can have up to 2560x1600.
So why cant I make my new monitor (27") have higher resolution than my older monitor (24") while using both screens? D:

Other info;
Older monitor 24" Asus w/ VGA, DVI, and HDMI.
New monitor 27" Samsung w/ VGA, HDMI.

Any help here? :)

My new monitor is a Samsung 27" LED SyncMaster S27B350H.
And my old one is an Asus 24" VW246H

When I checked the "Screen Resolution" page, it was on max, which was recommended as 1920x1080.

Going into the CCC and into the scaling settings worked!
It was on "Underscan 10%" and I changed it back to "Overscan 0%". Which made it work properly :)
I also ticked the box you mentioned.
THANKS, now I can enjoy my new monitor

The native resolution of the SyncMaster S27B350H is 1920X1080. Same as the Asus VW246H.

You'll get a larger image, but no more pixels.

There are high resolution (2650 X 1440, for example) 27" monitors, but they're expensive. Here's one that I wish that I owned:

http://accessories.us.dell.com/sna/p...n&sku=225-4148