Changed monitor and screen resolution got lower

I switched monitor of my Lubuntu machine, and the resolution is low now, however the monitor make and model is the same as the previous one.

Considering the fact that I didn't change any config on my Lubuntu, how I can increase the resolution. I played around with Monitor settings menu, but as far as I looked for, there is no option for changing the resolution. The output of $ xrandr is shown below.

$ xrandr
Screen 0: minimum 8 x 8, current 1024 x 768, maximum 32767 x 32767
VGA1 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768      60.00* 
   800x600       60.32    56.25  
   848x480       60.00  
   640x480       59.94  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

UPDATE

There is no /etc/X11/xorg.conf file and when I run following commands on console (ctl+alt+F1):

$ sudo service lightdm stop
$ cd /etc/X11
$ sudo Xorg -configure

I receive the following message:

No devices to configure. Configuration failed. (EE) Server terminated with error (2). Closing log file.

UPDATE

I ran

i@i-desktop:~$ gtf 1280 720 60 

  # 1280x720 @ 60.00 Hz (GTF) hsync: 44.76 kHz; pclk: 74.48 MHz
  Modeline "1280x720_60.00"  74.48  1280 1336 1472 1664  720 721 724 746  -HSync +Vsync

then:

i@i-desktop:~$ sudo xrandr --newmode "1280x720_60.00"  74.48  1280 1336 1472 1664  720 721 724 746  -HSync +Vsync
i@i-desktop:~$ xrandr
Screen 0: minimum 8 x 8, current 1024 x 768, maximum 32767 x 32767
VGA1 connected primary 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768      60.00* 
   800x600       60.32    56.25  
   848x480       60.00  
   640x480       59.94  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
  1280x720_60.00 (0x9a) 74.480MHz -HSync +VSync
        h: width  1280 start 1336 end 1472 total 1664 skew    0 clock  44.76KHz
        v: height  720 start  721 end  724 total  746           clock  60.00Hz

And then I ran

i@i-desktop:~$ sudo xrandr --addmode VGA1 1280x720_60.00

Now the resolution is higher but now it has horizontal and vertical offset, i.e. the screen doesn't fit the monitor.

UPDATE

I set the resolution to 1920x1080 60Hz and my monitor popped up a message saying that the optimum resolution is 1440x900 60Hz. So I ran the following commands and the problem is solved now:

i@i-desktop:~$ gtf 1440 900 60

  # 1440x900 @ 60.00 Hz (GTF) hsync: 55.92 kHz; pclk: 106.47 MHz
  Modeline "1440x900_60.00"  106.47  1440 1520 1672 1904  900 901 904 932  -HSync +Vsync

i@i-desktop:~$ sudo xrandr --newmode "1440x900_60.00"  106.47  1440 1520 1672 1904  900 901 904 932  -HSync +Vsync
i@i-desktop:~$ sudo xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
VGA1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1920x1080     60.00*+
   1024x768      60.00  
   800x600       60.32    56.25  
   848x480       60.00  
   640x480       59.94  
   1280x720_60.00  60.00  
   1368x768_60.00  60.00  
   1920x1080_60.00  60.00  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
  1440x900_60.00 (0xbb) 106.470MHz -HSync +VSync
        h: width  1440 start 1520 end 1672 total 1904 skew    0 clock  55.92KHz
        v: height  900 start  901 end  904 total  932           clock  60.00Hz
i@i-desktop:~$ sudo xrandr --addmode VGA1 1440x900_60.00
i@i-desktop:~$ sudo xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
VGA1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1920x1080     60.00*+
   1024x768      60.00  
   800x600       60.32    56.25  
   848x480       60.00  
   640x480       59.94  
   1280x720_60.00  60.00  
   1368x768_60.00  60.00  
   1920x1080_60.00  60.00  
   1440x900_60.00  60.00  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
i@i-desktop:~$ sudo xrandr --output VGA1 --mode 1440x900_60.00
i@i-desktop:~$ sudo xrandr
Screen 0: minimum 8 x 8, current 1440 x 900, maximum 32767 x 32767
VGA1 connected primary 1440x900+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1440x900      60.00*+
   1024x768      60.00  
   800x600       60.32    56.25  
   848x480       60.00  
   640x480       59.94  
   1280x720_60.00  60.00  
   1368x768_60.00  60.00  
   1920x1080_60.00  60.00  
   1440x900_60.00  60.00  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Solution 1:

If you open terminal and type xrandr it will display a list of possible resolutions for your current connection to the monitor.

You can read more about xrandr here. In particular adding modes.

To add a mode you must first create a new modeline using gtf or cvt. Copy the details from the modeline into xrandr --newmode. Then use xrandr to add that mode to your desired output. Finally set the mode using xrandr -s.

gtf 1366 768 60.00
xrandr --newmode 1368x768-60  85.86  1368 1440 1584 1800  768 769 772 795  -HSync +Vsync
xrandr --addmode VGA1 1368x768-60
xrandr -s 1368x768-60

It's important to note that if the new setting does not work properly or you are unhappy setting the new mode using xrandr -s then you can return to original by using xrandr -s 0 which will return to default.

Screen resolutions also have different formats and common resolutions can be found here. Some formats or resolutions cause the screen to overhang and it may just be a case of having to work out which ones fit and which ones don't, but by staying within the range of a format that works (eg. 16:9, 16:10) then you should go up in working style.