I recently upgraded from the i5-8400 CPU, GTX 1060 GPU system to the Ryzen 3700X CPU, Radeon RX5700XT GPU(Reference) system.
The previous GTX 1060 GPU had an AOC 3279 QHD Freesync monitor connected via the DP cable and was working very well. But with the same monitor and cable, there are some problems with the RX 5700 XT GPU that make me very uncomfortable using my computer.
First, video hardware acceleration does not work. I've tested Youtube Video hardware acceleration through Chrome, video file playback through DXVA, and in every situation, video playback was either severely lagged or not played at all.
Second, GPU health check programs such as Wattman or GPU-Z or MSI Afterburner are lapped at startup and no values are displayed at all.
Third, Freesync is forced to activate. Operation of the Freesync menu from the Radeon control panel does not change the setting. The same applies if you restart, disable Freesync, and then change the resolution or the rate of the injection. (Eddly, if set to 50 Hz, Freesync is disabled, but the above two symptoms are not resolved)
My Freesync monitor is not manipulating the Freesync setting in the monitor OSD. If you use a graphics card driver to change the Freesync settings, you will be able to activate them accordingly.
I reiterate that these three problems did not happen when I connected the same monitor and cable to the GTX 1060.
I tried to replace the DP cable or use the HDMI cable, but the symptoms remained unchanged.
It's also important to note that there was no problem with using a regular monitor that does not support Freesync with RX5700XT.
I'm about a month late on this one, but I just wanted to add that this is EXACTLY the problem I've been having. Or, at least, one of them -- there are so many. I'm wondering how many of them are related to the fact that my monitor, also an AOC, is apparently in FreeSync mode all the time when connected to this 5700 XT.
I'm connected to two AOC AG271QX monitors.
I also have an additional problem, related, which is that if I do enable FreeSync in the Radeon Settings and then launch a game, when I quit that game the card tanks and stops reporting sensor data and managing its self. This doesn't happen when I completely disconnect one of the screens.
I've contacted AOC about this and all they could tell me is that this is abnormal and that if the OSD states that the vertical refresh is FreeSync then the monitor is in FreeSync mode.
Something is very wrong here. Like you, with my previous card (a GTX 1080) this didn't happen. And FreeSync mostly worked with Nvidia's new driver support.
Were you able to figure anything out since your original post?