lspci -knnn | grep -i "display controller"
#And
sudo lshw -C video | grep -i "display controller"
sudo lshw -C video
Yes YouTube videos often jerk and my wallpaper is not so clear as in Windows.
If Ubuntu has a proprietary driver to offer you (or gets one later), it will be in the "Software & Updates" application under the "Additional Drivers" tab. AMD has updated their Linux driver support for Ubuntu 18.04, but it does NOT include your Radeon 520 model. The AMD support page is here... it currently only supports Radeon series 550 and higher.