MacBook + samsung syncmaster T220

Which port are you connecting to on the Syncmaster?

Probably the monitor has a defective EDID inside of it. You can read the EDID of the monitor using SwitchRes X by clicking on the button labeled "Print DDC" (or maybe "Print EDID" on later versions). It makes a text file from the monitor's EDID data. You can review the text file and see if 1680 x 1050 is in the driver data, but I suspect it is not.

If you already used SRX to set up the correct format, you can just uninstall SRX if you like and the format will remain as a selection within OS X's Displays Preferences.

If you are having trouble getting your Mac to "see" the correct resolutions of your monitor, it may be a problem with your VGA cable. I spent hours of time working with Apple support, diagnosing the problem, running tests, updating software and so on.

Despite the fact that the cable SEEMED to be working, I tried a different VGA cable and all my issues went away.

The 1680x1050 that I was looking for was magically there.

Guys... my problem is similar but not equal..

I can set the 1680X1050 resolution on my Syncmaster T220.
My macbook, that is connected to the monitor through a mini-DVI to VGA adapter, recognizes it immediatly.

The problem is that it doesn't uses the entire SyncMaster's screen.
It get the higher resolution, but it displays the things centered on the screen.
I just can't strech it to get full screen.

When I use lower resolutions, like 1024x768, it shows fullscreen.
But with 1680x1050 don't.

...

I start to suspect the VGA Cable...
but I tested it on a windows xp laptop and I got 1680x1050 fullscreen.
Now I suspect the mini-DVI to VGA Adapter or something software-related.

I tryed to reset PRAM, but got no success.

Have you ever gone through a problem like this?

Guys it worked fullscreen.

I opened the System Precerences > display.
on the arrangement tab, I unchecked the Mirror Displays.
Then I set 1680x1050 on the SyncMaster display.

As I want to use the SyncMaster as the main display, I moved the menu bar to the SyncMaster screen.
Now it is ok.

Sorry for bothering...
And I hope this helps those who get this problem.