Display works well with Ubuntu 19.10 and nouveau drivers with GeForce 7800 GT but when I upgraded to Ubuntu 20.04 the desktop works very weird, if I have two windows open or some window is not full screen it is disrupted badly.
But if I use for example Chrome on full screen it works fine and videos etc are displayed correctly.
I tried to go to use Nvidia drivers but it seems that this graphic card is so old that Nvidia ones are not available for Ubuntu 20.04.
Then I tried to install Kubuntu since I suspect that going up in Gnome version to version GNOME 3.36 in 20.04 could use some HW accelerations which are not working correctly with my graphic card. Kubuntu seems to have even more problems with my display so I removed it and since in Ubuntu 20.04 the display was so badly disrupted I installed again Ubuntu 19.10 and display is again working fine.
So something between 19.10 -> 20.04 causes that with GeForce 7800GT using nouveau drivers makes screen disruptions.
Are there some HW accelerations used by Gnome 3.36 which I could disable or should I try somehow GNOME 3.34 which is used in 19.10? Or are there maybe some updates in nouveau graphic driver which can cause my problems?
My graphics info now from 19.10 but 20.04 it were similar but display has lot of problems:
sudo lshw -class display *-display description: VGA compatible controller product: G70 [GeForce 7800 GT] vendor: NVIDIA Corporation physical id: 0 bus info: pci@0000:01:00.0 version: a1 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vga_controller bus_master cap_list rom configuration: driver=nouveau latency=0 resources: irq:51 memory:fd000000-fdffffff memory:c0000000-cfffffff memory:fc000000-fcffffff ioport:e000(size=128) memory:c0000-dffff