DELL U2711 Monitor Resolution with iMac 2010

[deacLL]

I can't get my new DELL U2711 27" monitor to achieve 2560x1440 resolution with my iMac 27" Fall 2010. Nothing higher than 1920x1080 which I could get for a lot less money than the U2711. ;-)

I updated all iMac software.

Is this likely to be a cabling problem, driver, other?

Thanks much,
Deac
;-)

 

[alust2013]

Most likely a cable problem, unless you have a miniDisplayPort to DisplayPort cable running it. How do you have it set up?

 

[Drewbie]

the max resolution for an analog cable setup is 1920x1080
a digital setup will be the 2560x1440 you are looking for.

so as the above poster has mentioned its most likely a cabling issue.... can you do an minidisplay port to HDMI ? or are you doing a minidisplay port to vga/dvi

 

[drambuie]

the max resolution for an analog cable setup is 1920x1080

A good quality shielded VGA cable can easily handle 2560x1600, which is the resolution used by some 27" 16:10 LCD monitors. Analog VGA can reach QSXGA resolutions of 2560x2048, which is the resolution of some very high res 5:4 CRT monitors. Most recent average graphics cards can output up to 2560x1600, or beyond, via VGA. The analog bandwidth for a 2560x1440 x 10 bit signal is 110.6 MHz. A good quality VGA cable will do ~400 MHz.

For an actual product reference, the Dell Ultrasharp U2711 mentioned by the OP will run at 2560x1440 via VGA input.

 

[deacLL]

Solution found

Thanks much to all the folks who provided the answer and insights to the answer. I'll summarize what I found and my current solution.

According to the User Guide (which I finally obtained), the only cables that support 2560x1440 into the DELL U2711 are these two inputs:
- Dual Link DVI, or
- DisplayPort

I bought a $99 miniDisplayPort to Dual LInk DVI which in fact does the job. I have a $10 miniDisplayPort to DisplayPort on order from Amazon.

I tried regular DVI , HDMI, and VGA inputs all of which failed. This point is (now that I found it) supported by the User Guide info which says:
Set the screen resolution to 2560 x 1440 (DVI and DisplayPort)
or 2048 x 1152 (VGA) or 1080p (HDMI, Component)
Somewhere it says that the DVI must be dual link. Wasn't obvious to me at first.

THANKS SO MUCH FOR YOUR HELP. I SPENT 3 DAYS TO FIND WHAT, IN THE END, IS A VERY SIMPLE ANSWER.
HAPPY HAPPY HAPPY.

 

[Drewbie]

A good quality shielded VGA cable can easily handle 2560x1600, which is the resolution used by some 27" 16:10 LCD monitors. Analog VGA can reach QSXGA resolutions of 2560x2048, which is the resolution of some very high res 5:4 CRT monitors. Most recent average graphics cards can output up to 2560x1600, or beyond, via VGA. The analog bandwidth for a 2560x1440 x 10 bit signal is 110.6 MHz. A good quality VGA cable will do ~400 MHz.

For an actual product reference, the Dell Ultrasharp U2711 mentioned by the OP will run at 2560x1440 via VGA input.

im sure the monitor will support that, but the computer will not if its VGA. either way they got it working...