We are currently investigating various VNC issues in Fedora:

• Gnome 3 has become too heavy for a VNC session. And while Fedora 18's Gnome provided a fallback mode, this doesn't work any more in Fedora 20 and up. The “new” Gnome Classic session type, seems to require the same level of accellerated graphics as the full Gnome desktop, so this doesn't help. Cinnamon 2 seems to suffer from this same problem, but is usually able to go into “fallback” mode when it detects such a situation. The best alternative is to use another desktop in VNC; we have sample configs avialable for most of the desktop environments. Use eg SfinxUpdate xstartup-kde for the KDE version of .vnc/xstartup, or xstartup-mate, etc. See comments in these files for more possibilities to start other desktops. For Cinnamon, you can use cinnamon-session –session=cinnamon2d in your .vnc/xstartup file

• A new alternative to VNC is X2GO. It is an integrated client that handles configuration, ssh connections and starting a desktop session, all from a simple GUI. As for desktop choices: Gnome and Cinnamon are failing (or falling back to “fallback” mode) here as well; the other desktops work properly, and MATE, KDE, XFCE and LXDE can all be selected directly from the session preferences window, as well as simple desktops like OpenBox.
  

Unfortunately, X2GO is falling behind the times a bit. Currently (Fedora 37), KDE no longer works, and MATE will start without window decorations, leaving XFCE, LXDE and OpenBox as the only usable session types.

• Another workaround is, to view your actual desktop session through VNC or x2go.
  • In Gnome: open gnome-control-center, go to category Sharing and enable Screen sharing
  • For x2go, open “X2go desktop sharing” from the menu and turn it on from its panel icon. Now you can connect to display 0 on your desktop and work on your actual login session
  • x0vncserver basically does the same thing (after configuratrion, read the man page for details)

• There is also VirtualGL, which is supposed to handle the 3D OpenGL calls in the local X server, and send the resulting rendered image to the remote X or VNC session. However, in order for this to work, the user must have access to the running session on :0 on the actual hardware. There are insecure ways to set this up, but that will not be done here. The only way to make use of it is, to be logged in on the console, and run a vncserver as the same user, using VirtualGL (eg containing vglrun gnome-session)