imac late 2015 to LG 27uk850w 4k display

Updated on 22-02-2019 in Adapters and Cables
1 on 21-02-2019


I’ve purchased a LG uk850w and a CAC-1170 adaptert to extend my iMac late 2015.

When i plug in the cable from thunderbolt 2 to hdmi the LG is flickering by 3840×2160 30Hz. If i try to enable 60 Hz or 59 the LG screen goes black.

Is the CAC-1170 the right adapter or is the Intel HD Graphics 6000 to weak to go with the 4k display

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0 on 22-02-2019


Thank you for your question

The intel HD Graphics 6000 should be able to support your LG uk850w at a resolution of “DP 1.2/eDP 1.3 (max. 3840 x 2160 @ 60 Hz) or HDMI 1.4a (max. 3840 x 2160 @ 24 Hz)”.

May i ask what cable you are using? some cables are not able to put through 3840×2160 @60hz however this might be rare i would like to rule out the limitation of the cable. If this does not work i would advise you to do a firmware upgrade on the CAC-1170, see link below:


Latest available Firmware is “V7.61 or 0.61”:

Hereby Latest available firmware for CAC-1070 / CAC-1170.

Hereby the dropbox link to the latest available firmware called “0x61” (or V7.61) and the update procedure. 

When running the update, connect adapter to system and screen to adapter and turn on.

Just copy onto desktop and run as administrator.

The updater program does not work on MAC OSx, so updating Firmware needs to be done on WIN or Bootcamp system.


For additional questions or information you can also contact [email protected]

Kind regards

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