[iamterrific]

I have a Powerbook with a 128 MB ATI Mobility Radeon 9700: Graphics card. The display I am hooking up via DVI is the Dell 24 in which supports a resolution of 1920x1200. The display is awesome the best display I have ever purchased.

The problem is when I connect the display to the Powerbook and mirror displays the Dell display cannot run the full resolution of 1920x1200. The laptop must be closed for the 1920x1200 resolution to be displayed on the Dell. My friend who has an old powerbook and the same display has no problem running both displays at their native resolutions 1920x1200 and 1280 x 854.

Any help or ideas would be greatly appreciated.

[hickey]

I believe you have to do screen spanning, not mirroring. I could be wrong, and if I am Im sure someone will tell me.

[iamterrific]

Yes, screen spanning does work but not mirroring.

[icruise]

Well, in order to "mirror" displays, the displays have to be using the same resolution (in this case, the lower resolution of the PowerBook's display). Is there some reason that you want to mirror and not span?

[iamterrific]

When I turn on mirroring it sets both displays at their native resolutions but the large dell display does not fill the screen and it reads 1920x1200. The window is about the size as the powerbook screen. Not sure why it doesn't completely fill the screen. Thanks for all the help.

[ibook_steve]

When mirroring, the external display at first should go to the same resolution as the Powerbook. For example with my 12", when I mirror, the external display goes to 1024x768. You can then change the resolution of the external display in the displays preferences. For example, after mirroring, if I change the external display to 1600x1200, I get the 1024x768 Powerbook display on the external display surrounded by black. Some displays support stretching, so you wouldn't see the black around the display, but this distorts the image. I'm guessing your external does not support stretching. What are you trying to do anyway?

Steve