Comment 4 for bug 565980

I experienced a similar problem.

I have a GeForce 8500 GT and a 1920x1200 monitor (Samsung).

Boot menu and splash screen are displayed in a very low quality and with strong flicker.

When you use the command vbeinfo (in Grub), no display mode is compatible with the monitor resolution.

By default, the 640x480 mode is selected and it is a degraded mode.

I tried several solutions without success: vga=xxx, GRUB_GFXMODE=1920x1200, ...

I finally got an improvement in making these changes:

1) Add "set gfxpayload=keep" after "set gfxmode=${GRUB_GFXMODE}" in /etc/grub.d/00_header.

2) Remove the # before GRUB_GFXMODE in /etc/default/grub and add the following modes: 1600x1200x24, 1600x1200, 800x600x24, 800x600:
GRUB_GFXMODE=1600x1200x24,1600x1200,800x600x24,800x600

3) Add this additional line under GRUB_GFXMODE:
GRUB_VIDEO_BACKEND=vbe

4) and ensure this line is commented:
#GRUB_TERMINAL=Console

5) Update the grub settings:
sudo update-grub

6) reboot

7) Adjust the zoom mode of the monitor and press "auto" to adapt the view.

It seems that the choice of the resolution must have a consistent ratio between the monitor and the selected vbe mode. For example, 800x600 also works well as the vertical resolution of the monitor is 1200.