Mac Pro treats Dell U2413 monitor as Television

Good day, Experts!

We purchased one of our designers a Mac Pro.  The system works well, but it treats the display-port attached U2413 as a TV, eliminating some of the resolution options like refresh rate.  I meant to capture the picture with the scaling selection, so you can see there are only three choices; however, I think the main issue is the fixed 60 hertz.  In short, the picture being jagged is the challenge for the user.

Anyone know of the fix to this.

Kevin
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Kevin CrossChief Technology OfficerAsked:
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Kevin CrossConnect With a Mentor Chief Technology OfficerAuthor Commented:
Use thunderbolt to DVI connector.
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Eoin OSullivanConsultantCommented:
OSX 10.9 Mavericks offers less resolution options in the "Scaled" list than  OSX 10.8 or earlier did. This can be a problem if the resolutions that it "thinks" your monitor supports are incorrect.

The fix is quite simple but not commonly known .. you can show the extended list of possible resolutions in Mavericks as follows:

In the Displays preference pane, hold down the option key and then click the "Scaled" radio button. This will toggle on and off additional resolutions for the screen.
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Kevin CrossChief Technology OfficerAuthor Commented:
Thank you for the reply!  That trick definitely fixes the "Scaled" list.  However, it appears the issue is with the refresh rate, which is stuck at 60 hertz still.
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Eoin OSullivanConsultantCommented:
Refresh rate is not really applicable to LCD screens .. just the resolution .. see the following Apple forum which covers the issue.  Refresh rate is really only applicable to older CRT displays.
https://discussions.apple.com/message/22151620#22151620

The optimal settings for that screen according to Dell are 60Hz anyway
Optimal resolution:   1920 x 1200 at 60 Hz
See the tech specs on their website
http://www.dell.com/ed/business/p/dell-u2413/pd

Try choosing that resolution (1920 x 1200) and see how it behaves
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Kevin CrossChief Technology OfficerAuthor Commented:
That is the resolution she is using and it doesn't show fonts correctly.  At lower resolutions, it gives higher refresh rates that make it not look like a TV.  I may not be explaining the issue appropriately, but the screen does not show optimally.  

Thank you for the help, though!

P.S. Another Mac user had a similar issue, and he fixed by changing the refresh rate.  That is the only reason I mentioned that.
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Eoin OSullivanConnect With a Mentor ConsultantCommented:
OK .. it seems that because OSX is not familiar with that monitor it is incorrectly identifying it as a TV and no matter what resolution or refresh rate you choose it is using an incorrect colour space.
The reason is that the DisplayPort uses YCbCr colors instead of RGB to drive the
display, which limits the range of colors and apparently causes the display to apply some undesired post processing.  The problem can be solved by overriding the EDID data of the display in order to tell OS X that the display only supports RGB.

There would appear to be a fix/patch but it involves a little bit of messing with OSX system -
http://www.ireckon.net/2013/03/force-rgb-mode-in-mac-os-x-to-fix-the-picture-quality-of-an-external-monitor

this page refers to someone else fixing the U2413 with this patch too
http://embdev.net/topic/284710

Here is the script on GitHub
https://gist.github.com/adaugherity/7435890

Happy editing
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Kevin CrossChief Technology OfficerAuthor Commented:
We already forced the monitor to RGB using that article.  It did not work; however, I think the user had an older version of the script, so I sent her a link to the newest version 5 minutes ago to test again.
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Kevin CrossChief Technology OfficerAuthor Commented:
Okay.  She tried, and it still doesn't work.  Ugh.
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Eoin OSullivanConsultantCommented:
There are enough posts out there to indicate that the incorrect identification of the monitor's EDID data is the problem ... if the script doesn't work .. then I'd keep digging in this area or possibly contact Dell to see can they offer a patch/script for OSX10.9.
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Kevin CrossChief Technology OfficerAuthor Commented:
Same thing I told the user, so it is good to get validation here.  I figure if there was a different solution, the Experts here would know.  She even called Apple, so we will see what happens.  

Thanks for the help!
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Eoin OSullivanConsultantCommented:
I'd be very surprised if she gets any joy from Apple .. they don't care to troubleshoot & support 3rd party hardware when they sell their own displays.

The solution is in that EDID script .. just might take a bit of fiddling about
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Kevin CrossChief Technology OfficerAuthor Commented:
I agree.  I will update the question when I have a final resolution.
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Kevin CrossChief Technology OfficerAuthor Commented:
The fact that the DisplayPort uses YCbCr colors instead of RGB was indeed the issue; however, the EDID script would not work for the user.  I believe this will work for others, though, so I am adding as a helpful solution.  For others, use DVI connector.
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