Does your computer have integrated Intel graphics as well as the Radeon card? If so, have you checked to see which one SketchUp and LayOut are actually using? In SketchUp you can see that by going to Window>Preferences>OpenGL.
If it is the Radeon card that is being used, you might try updating the card’s drivers.
When you installed SketchUp 2018 Pro, how did you do it? Did you just double click on the downloaded installer file to launch it or did you right click on the installer and select Run as administrator?
And thanks for updating your profile.