I recently bought a new MiniPC which now substitutes my old desktop. I immediately wiped out the preinstalled Windows with Linux Mint Cinnamon. Everything is fine now but when I view HD SAT channels I get intermittently annoying artefacts. So I started to debug the issue and detected following tools which helped me to find the root cause for this issue. 

radeontop and amdgpu_top

So I found out my VRAM of 512MiB is quite small. Cinnamon already occupies 200MiB and Xorg again about 200Mib. Thunderburd also used a lot of VRAM which I didn't understand. But you can turn of hardware acceleration in Thunderbird to reduce the VRAM usage. I have no idea why Thunderbird uses VRAM.