Currently its not using the full res - I only have the display options of 1280 x 720
iMac (27-inch, Late 2012), OS X Mountain Lion (10.8.3)
System Preferences>Displays and select: Resolution 'Best for built-in display'.
Sadly this is what it is currently set as
I suppose that you don't have any external display connected, right? I suggest you to reset the PRAM first, before trying other things.
A PRAM reset restores the resolution to factory settings, too. After resetting it, your iMac should be using the 2560x1440 resolution. If not, open System Preferences > Displays, choose "Scaled" under "Resolution" and tell me what resolutions you see.
Another question: did the iMac come with that resolution or you used your computer before getting this resolution?
Hi - yep no external displays
the first time i turned it on, it was like it . It once had th high display after a reboot but now its back to 1280x720 and I cannot change it.
It is only about 2 weeks old. Ill try resetting the PRAM now
If it is two weeks old contact Apple. You get 90 days phone support. Or locate an Apple Store and make an appointment.
resetting the PRAM didn't seem to work - still only giving options of 1280x720
In that case, contact with Apple > http://support.apple.com/kb/HE57 As you have just bought the iMac, you can return it and get a new one for free. Maybe the problem is fixed just reinstalling OS X, but in my opinion, it's better to return the iMac and get a new iMac that works without doing any of those things
sadly = this is the last option as it took 6 weeks to get delivered !
If it's a base model, you can get the iMac replaced inmediately at an Apple Store (if you can go to one). If you have a build-to-order iMac (you customized the hardware), this may take more time.
There were delivery problems with the latest iMac, but they are solved now
As others have said, put it back in Apple's court to sort it out, but I realise it must be a big disappointment after waiting for so long.
Even though you shouldn't have to do any mucking about to get it working properly, you could try re-installing the OS. Maybe start a dialogue with Apple first - they may suggest that you do that before starting the palaver of changing the machine.
You've got free telephone support for 3 months (3 years if you've got the extended AppleCare).
Thank you all - it is indeed a customized version. I have a call scheduled tomorrow with Apple Support
Really, don;t know why anyone would mess around with a brand new Mac. If I just spent 2000 on a system I'd expect it to work out of the box with minimal need for tweaking.
Call Apple or make an appointment at the Apple Store. There may be a simple fix that Apple knows of (we're all just users here like yourself).
You are welcome
How can I set the 27" Imac to have full resolutions not 1280x720
