I just wanted to warn anyone thinking of upgrading to Linux if you have an AMD/ATI card don't do it!
I'll post a few ways to get the card installed but it will never work right. I tried a Gigabyte RX580 & RX560. The screen looks great but games and videos are a mess! AMD/ATI makes drivers for the cards but they make it even worse! If you're not going to be watching movies or playing games you are fine with the stock "Mesa" drivers installed on a Ubuntu/Xubuntu install. If you try to play any game or watch netflix you are going to be in LAG FRAME RATE HELL!
What sucks for me I just got rid of all my best Nvidia cards.
The system, videos, games all run fine on a little EVGA GTX 1050 SC 2 gigs.
Pop in a 4 gig RX 560 or a 8 gig RX 580 and it runs horrible. And runs even worse once you install the AMDGPU Pro drivers.
I tried Xubuntu 16.04.2 which I use with an EVGA RTX 2080 TI Ultra XC! Some people believe it's the older version on Xubuntu/Ubuntu that is the problem. It doesn't support NEW VIDEO CARDS LOL Well my 2080 TI is dam new and works just fine!
So after hours of tweaking, installing, uninstalling, purging, re-installing... I broke down made an image back-up in case it didn't work so I could go back to 16.04.2. And I upgraded to the broken 18.0.2. Well it was better! Netflix would play at almost a watchable frame rate, games were still horrible. And best of all it's all TERMINAL COMMANDS to control the fan speed! No GUI (THAT WORKS) so both cards run at max fan speed even if the card is ICE COLD!
So to recap Xubuntu/Ubuntu 16.04.2 or 18.04.2 DO NOT WORK WITH AMD CARDS. You can try and after hours of work you can get your RX 580 run half as nice as a 2 gig Nvidia card.
But if you want to fight it here is how to do it.
First download the drivers for your card and version of Linux.
Then open a terminal window and unzip the download.
1. Type in: cd Downloads (hit enter if the file is in your downloads folders. Should look like this ~/Downloads$)
2. Type in: tar -Jxvf amdgpu-pro-18.20-XXXX.tar.xz (amdgpu-pro-18.20-XXXX.tar.xz should be the name of the driver you downloaded) Hit Enter.
3. Go to the downloads folder and RENAME the unzipped folder to something EASY TO TYPE IN! Now back to the terminal window.
4. Type in: cd ~/Downloads/amd-18.20 (amd-18.20 id what I renamed the folder to or type in the name of the folder) Hit Enter.
(Should look like this ~Downloads/amd-18.20$ or what ever you named it)
5. They will two versions amdgpu-install and amdgpu-pro-install. If you have anything RX 5 or higher you would use pro. They don't say that they just say newer then Vega 10. Then when you look it up everything says Vega 11 is newer then 5 series. But I already did the work! 4 series or older "amdgpu-install" anything RX 5XX or newer "amdgpu-pro-install"
And of course there are two of them! Neither one works so you can try one or both. But remember you must uninstall and autoremove before each try. So if you have a RX anything 5 or higher you use "amdgpu-pro-install" Back to the terminal window (yeah the nvidia drivers can just be install in Software & Updates select the driver, click install you're done)
6. Type in: sudo ./amdgpu-pro-install -y --opencl=pal or ./amdgpu-pro-install -y --opencl=rocm (Hit enter it will download about 350 megs of stuff) I tried both =pal and =rocm both were just bad.
7. Reboot.
The screen will look nice but that's about it.
If you don't install the AMD drivers videos & games play better then with them!)
After the reboot check it, look for tweaks, adjust the fans in a terminal windows with these commands.
Fan speed:
echo 185 > /sys/class/drm/card0/device/hwmon/hwmon1/pwm1 (adjust the 1 up to the speed you want I went to 15)
Know your fans sound good but still no joy on using the system!
So go back to the terminal windows and remove the AMD driver.
1. Type in: amdgpu-uninstall (hit enter)
2. Type in sudo apt autoremove (hit enter)
3. Reboot
Now you can try the "Mesa Drivers" open another terminal window.
1. Type in: sudo apt-get update (hit enter)
2. Type in: apt-get install mesa-va-drivers (hit enter - it may say they are already installed)
Then if they are already installed or they just don't work do this. Yes back to the terminal window.
1. Type in: sudo apt-get update (or just hit or arrow key up anything you EVER type in a terminal window stays there! Not like crap DOS! Hit enter)
2. Type in : add-apt-repository ppa:ubuntu-x-swat/updates (These are beta, newest releases, newest fixes... Hit Enter)
3. Type in: sudo apt-get update (or arrow key up - hit enter)
4. Restart
Now test those, use terminal to adjust your fans again. You will need to do that after every reboot unless you make a fan script. Now some people claim the Mesa Drivers work on Xubuntu/Ubuntu 16.04 and up. They were better but still HORRIBLE game frame rates and videos (IF THEY WOULD PLAY) were choppy. I also heard that AMD cards work in Mint.
To uninstall Mesa Drivers.
1. sudo apt-get remove mesa-va-drivers
2. sudo apt-get remove --auto-remove mesa-va-drivers
3. sudo apt-get purge mesa-va-drivers
4. sudo apt-get purge --auto-remove mesa-va-drivers
Or save yourself a few days of misery and just use ANY Nvidia card. Install a driver and --cool-bit=4 (ONE TERMINAL COMMAND) Restart ONCE and the system runs perfectly!