I built my desktop with Ubuntu 18.04 LTS today, when I booted in the display was laggy, slow to swap windows, low frame response in youtube video playback.
I updated OS, rebooted, no different. I did a quick google in case the card required a video driver, I following this link, but once I got to the point of modifying the xorg conf I was unable to find it in that directory. Rebooted and the computer froze at the fade in for the login.
I removed the AMD drivers, added
sudo add-apt-repository ppa:graphics-drivers/ppa
updated, rebooted and was able to login, but the window switching is still laggy.
Does anyone have any options I can try?