Two problems: I cannot change the pixel format at all when it is at 4K. Second, even if I change the pixel format to YCbCr 4:2:2 when I am under 1080P in the hope that it might persist or carry over when I switch to 4K, I still cannot change the pixel format and, as a result, I cannot increase the bit depth to 10-bit or 12-bit when at 4K.
If you set the resolution to 4K 3840x2160 and then set the refresh rate to 30Hz, can you see the pixel format options? I can only see them at 30Hz, but once I switch to 60Hz they disappear. When i'm at 30Hz and choose 4:2:2, my screen turns black and will not come back on, so there's no way for me to change the color depth from 8 bpc to anything else.
Any update on this? The 1060 GTX came out today and i'm still within my return period. If this is going to be fixed soon, i will wait. If they can't identify the problem, then it's most likely a defective card, and needs to be returned anyway. Please let me know.
Well... I've spent too much time fooling around with this card. I need the 4k 4:4:4 for work (not for gaming). It's really unfortunate this card has this problem. I'm returning my RX 480 today, and I'm going to spend $10 more and get the 1060 GTX. Thanks for your help.
Funny enough, I also just returned mine for similar reasons. This video card would have served double duty as an HTPC video display device, but since the support here is slow and initially just wanted to tell me it works on their system and it should work on mine, I am abandoning AMD this generation. What a pity, too, since I feel they are making a nice comeback and all with Zen en route for the fall, I wanted this to be like the Athlon 64 glory days. But as time has shown me, Intel and NVIDIA's support has been superior again and again, who have always made me feel like my problem is legitimate and real, even if I, as a customer, perhaps may be mistaken. Customer service 101. Since I have a vast collection (10,000s of episodes and movies) of SD, HD and 4K video content that I play back through my device and I largely prefer 10- and 12-bit color as it has the huge advantage of vastly reducing color banding when scaling to 4K, I am forced to do myself a favor and get the product that works seamlessly, without all the headaches. Besides, the GTX 1060 is neither the power hog or sultry steam box the RX 480 comparatively is, so my power bill and case temperature will thank me.
The saddest thing is, these are very basic features that don't even work. Maybe one day AMD will return to their glory days, but i'm not holding my breath. This has been a horrible experience for me, i probably won't be purchasing another AMD product for a very long time.
There are more reports of the same issue here: https://www.reddit.com/r/pcmasterrace/comments/4ste6a/rx_480_no_video_using_hdmi_with_4k_60hz_444_tv...
The guy found the same solution we did, he bought an Nvidia card.
I've been playing with my GTX 1070 and I know what your issue is. Just like with the AMD card the GTX 1070 only supports the 12bit mode if you are in 4:2:0 chroma. The reason you couldn't change to 4:4:4 mode with the AMD card is you must have already been in 12 bit mode. It is the same with the GTX 1070, if you are in 8 bit mode then you can switch to 4:4:4 or RGB, but if you are in 12 bit mode, then you are restricted to 4:2:0 only. The GTX 1060 will be exactly the same as your RX 480 as this is the maximum bandwidth of HDMI 2.0. You can't have both. And since 10 or 12 bit color is practically useless, you should select 8 bit color and 4:4:4 4K 60hz, regardless of which card you are using.
If you were in 8 bit color and you couldn't choose 4:4:4, that doesn't make sense as I can and the other person can choose it, so it would be a rare bug. I saw your picture show your desktop color depth as 32 bit but that is a totally different thing. You must go into the AMD settings and choose 8bpc before trying to choose 4:4:4. See the image:
The unfortunate thing, is that HDMI 2.0 is terrible, because they wanted to re-use the same cables and hardware that HDMI 1.4 used. I'd much rather have a display port connection for my TV. I've been returning TVs because I can't get a single one to work with 4K and a long cable. There is no nirvana on the nVidia side as I've been having the same problems with my GTX 970 and 1070. One guy bought an LG OLED for 6,000 dollars and a GTX 1080 and the only way to get the image to work was to turn off the audio over HDMI.... sigh... I'm waiting for HDMI 3.0 now