This issue started a while ago for me.
I had the Sapphire R9 270x Dual-x card and drivers worked fine on it. Sometimes the optional ones had issues and I would keep old ones until a new one worked. About a month and a half ago I decided to upgrade and got a stock RX 480 8GB not knowing the RX 580 was about to be released for cheaper than the RX 480. Good thing it was too as the RX 480 I purchased off ebay was crashing the whole computer constantly. I thought it was completely defective when I first got it as when I uninstalled AMD drivers and restarted I would have to unplug/replug the HDMI cable for the signal to come up. Then I had to do that repeatedly when logging in and changing the screen resolution until I had installed the drivers again. Then once they were installed I had to go through each driver version backward until I found one with working HDMI Audio after reboot. That happened to be 16.5.1. After finding the working driver I found updating parts of the driver or the driver in whole from that working one did not produce working HDMI Audio. I returned it within a week and saw the RX580 was out.
I picked up an MSI Gaming + 8Gb RX 580 from newegg. Brand new in the box. I put it in my computer to find it has the exact same issue as the RX 480 had with windows basic VGA drivers. No problem, I worked around that little bug. Found turning my monitor off and on again was less wear and tear than unplugging and replugging the HDMI cable. I also picked up a Displayport to HDMI cable just to make sure that it wasn't just a bad cable or port. I've used this HDMI with the R9 HDMI 2.0 port so I don't see why it would fail me now. The issue is the same on all cables. No worry, once the driver is installed it finally works. Everything works except the HDMI Audio. AGAIN! Only I tried every driver installing in every way. 16.5.1 does not work with the RX 580 like it did the RX 480. I tried every cleaning tool. Tried the included CD-ROM driver first and many times since and it has never once worked. Until I found that the only way to use my card is to uninstall and reinstall the display driver and NOT REBOOT the computer. As soon as the computer reboots the AMD HD audio is nowhere to be found. I tried using the basic Microsoft HD audio drivers and rebooting with those, but it still forgets those too. They work as well as the AMD ones before rebooting. I've tried unplugging all other peripherals, disabling the onboard audio, updating every part of windows, uninstalling reinstalling all of microsoft .net, I have boot time scanned my computer for viruses or malware and it was completely clean, I don't normally have antivirus and quickly removed after scanning, no matter what I do the AMD Display driver somehow kills my HDMI audio on reboot. When I do uninstall and reinstall the driver it forgets my card since it hasn't rebooted and the games don't recognize the card for default settings. I uninstalled raptr and all sorts of junk to try and get this card to work.
Does anyone know how to get these drivers to function after reboot?
MSI 970 Gaming Mobo
RX 580 Gaming +
Windows 7 64-bit SP1
2TB WD HDD
850 Watt power Supply
I know it's nothing to do with the power since these cards have a lower power draw than the R9 270x.
It's funny, when running Windows 7 startup repair booting off my Win 7 disk the HDMI does the blackout thing too. So no matter what drivers they make this card can't even handle basic Windows 7 installs without trouble.