This message was posted on behalf of Intel Corporation
Thank you very much to N. Scott Pearson for the suggestion provided previously.
Besides trying to test the NUC with a high quality HDMI cable, also for testing purposes please test the NUC without the A/V receiver, connect it directly to the TV, just to rule out a possible compatibility problem with it.
By using the HDMI port you should be able to get 2560x1600@60Hz as max resolution, as you can confirm on the following link:
Just in case the processor on the NUC works with Intel® Iris™ Graphics 6100 controller, on the link below you will find the latest version of the graphics driver for it:
You can also try the beta driver as well:
Any questions, please let me know.