AMD graphics card

1. Already ran "sudo apt install matlab-support" ? As you installed PTB from us, you need to run it, and answer the various questions with "yes". It will fix some of Matlab's unique brokeness.

2. "uname -r" should report a Linux 4.8 kernel. If it doesn't do that already, "sudo apt install linux-lowlatency-hwe-16.04" and reboot. I don't think the 4.4 kernel already supported your R480 card.

3. What's the output of PTB in Matlab's window?

4. XOrgConfCreator if it works will only create the config file, but not apply it. For that you have XOrgConfSelector, which allows to switch between the standard display setup (Option 0) or any given number of config files created by XOrgConfCreator, so one can switch between different configurations, e.g., for different experiments. You need to logout/login again after using XOrgConfSelector.