My machine runs on slightly old AMD hardware, especially display - Radeon HD 6290 card - which AMD doesn't have linux support anymore.
KDE plasma has extremely irritating display flickering and not-refreshing issues, be it Deb or Fedora.

It happens only in KDE Plasma and not GNOME, so this is a KDE issue, not GNOME (or Cinnamon et al).

If the same driver is used by both KDE and Plasma, why does this issue occur only in KDE? Is there way to find it out and fix this issue? I really like to use KDE Plasma, and hate to have to use other desktops.

TIA.
Ravi

Hello,
I have the same problem.
openSuse leap 42.3
please, any solution?

I solved in great measure the flickering y screen tearing: reset theme desktop and fonts system

How did you reset your theme? I've tried selecting each theme and my problem as documented in
viewtopic.php?f=66&t=143118 with screen unusable by people but fine in screenshot doesn't change.