DisplayPort to HDMI cables were not working. The problem was that neither of the two cables ordered could display the image in 4K mode. They were only displayed in 1080P mode and only output the sound on the stereo channel! I needed 4K display capability for movies or movies and 7.1 audio playback. After carefully testing the cables with various devices, I came to the conclusion that the power rating is either incorrect and limited to 1080P, or the cables are defective from the factory. Unfortunately I have to recommend a slightly more expensive cable from another company which will hopefully be reasonably priced and quality controlled to ensure it will work in a 4K system.