I have two monitors both Dell Ultra Sharp models, one is 24" and the other 30".  I am running Win7. 

Both monitors are connected to a Radeon HD 7750 via HDMI.  The desktop is extended onto both.

The 24" monitor is 1920X1200.  Unfortunately so is the 30"monitor.  Is there a way to set the 30" to its max resolution of 2560x1600?

Thanks for your help.

Why use dvi adapted to HDMI when you can use displayport especially for the 30"?

Anyhow.. that doesn't make any sense.. desktop extended onto both. What does that mean?

#1: Phenom II C2 955BE @ 3.6, Antec Kuhler 920, Gigabyte GA-MA790FX-DS5, Asus 5870/V2, ASUS Xonar D2X, 4 x 1gig OCZ2N1066SR2GK @800, Antec Truepower New 750, Arc Midi, Win8pro x64 upgrade
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Sorry if I wasn't clear.  The video card has two HDMI ports and one for Display port.  There is no DVI.

I got two HDMI cables and connected the card directly to the HDMI ports on the monitors.

"Desktop extended onto both" means that the desktop displays on both monitors.  The other option in setup was to duplicate the desktop.

Is there a limit on resolution of HDMI?  I was told by Dell when I purchased the video card that it would drive the 30" monitor at 2560x1600.

HDMI 1.3+ has the ability to display 2560x1600, but odds are you have only 1.2 on the graphics card, monitor, or both.  You need to use Dual-Link DVI or DisplayPort with a 30" monitor.

What Thanny said..

Just what make/model of vidcard is this. The ones I saw had dvi, hdmi, DP.

Just for clarification..

What you have is Desktop extended to 2nd display, not "desktop extended onto both". That would only make sense if you had 3 displays and you were extending both left and right.

#1: Phenom II C2 955BE @ 3.6, Antec Kuhler 920, Gigabyte GA-MA790FX-DS5, Asus 5870/V2, ASUS Xonar D2X, 4 x 1gig OCZ2N1066SR2GK @800, Antec Truepower New 750, Arc Midi, Win8pro x64 upgrade
#2: Athlon 64 X2 4200+, AGP 1950pro, Audigy 2, Asus A8V-D, 2gig ram,  Enermax 465P, Antec900. Now on Win8pro cat 10.2