xrandr set resolution

If you have too low resolution and you want to make a higher resolution, you can use xrandr. Examples:

Computer reqognizes 1024×800 resolution when running xradr command.
To test and set new resolutions:

cvt 1280 1024

… the output
# 1280×1024 59.89 Hz (CVT 1.31M4) hsync: 63.67 kHz; pclk: 109.00 MHz
Modeline ”1280x1024_60.00” 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync

…. to make a new resolution
xrandr --newmode "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync

xrandr --addmode VGA1 1280x1024_60.00

… to test the resolution open Displays or run a command
xrandr -s 1280x1024

Example 2:

cvt 1366 768

… the output
# 1368x768 59.88 Hz (CVT) hsync: 47.79 kHz; pclk: 85.25 MHz
Modeline "1368x768_60.00" 85.25 1368 1440 1576 1784 768 771 781 798 -hsync +vsync

…. to make a new resolution
xrandr --newmode "1368x768_60.00" 85.25 1368 1440 1576 1784 768 771 781 798 -hsync +vsync

xrandr --addmode VGA1 1368x768_60.00

… to test the resolution open Displays or run a command
xrandr -s 1368x768

NOTICE THAT

xrandr can make so big resolution that you get a black resolution or some old display can literally explode, because it has no self-protection. If you get the black screen, press Ctrl F2 and Ctrl Alt Del for rebooting the computer.

WordPress shows the commands wrong, so read xrandr

TO SET THE RESOLUTION PERMANENT

Read the next article
https://wiki.ubuntu.com/X/Config/Resolution#Setting_xrandr_changes_persistently

If you can´t find the proper resolution, old Knoppix, Mepis and antiX can make a good /etc/X11/xorg.conf file, which can be copied to an problematic system.

wonder knoppix.xorg.conf