MacOS – External Display limited to 1080p after 10.9.2. update

displaymacbook promacos

I have an Asus PB278 (WQHD 2560×1440) connected via HDMI cable + HDMI-Thunderbolt adaptor to my MacBookPro Late 2011.

Until the update to OSX 10.9.2, I was able to use full WQHD resolution on my external Monitor. Since the update, the highest resolution I can choose is 1080p. It seems that the Monitor driver is broken or simply wrong.

Monitor Settings

Also, in the system information, the monitor is listed as 1080p TV ?!+

System Information

Has anyone the same problem?
I did not find an update for the monitor profile. Is this a fancy Mavericks bug?

I've zapped the PRAM but that did not change anything.
In Monitor Settings, tried to "detect monitor" and listing all resolutions – to no avail.
Thanks for you help

Best Answer

The problem is Mac OS X. It is limited (in software, in the drivers) to a certain pixel colour clock rate for the HDMI port. The hardware in the Mac is more than capable of driving your WQHD monitor at 2560 x 1440 etc., but you can't do it via HDMI as the operating system's interface to it is essentially crippled in software.

It'll work via the DisplayAdapter port, though. The downside is that the single Thunderbolt connection will be taken, and you won't be able to connect to your monitor and other gear at home.