Under the section “Device.” Unfortunately, I have no such file
Try creating your own xorg.conf file, placing it in this location will override your X settings after restarting X or simply by restarting the computer.
mkdir -p /etc/X11/xorg.conf.d/
cp /etc/X11/xorg.conf.d/xorg.conf /etc/X11/xorg.conf.d/xorg.conf.bk # in case it exists
cp /usr/share/X11/xorg.conf.d/10-monitor.conf /etc/X11/xorg.conf.d/xorg.conf
The content of /etc/X11/xorg.conf.d/xorg.conf would look like (adding your options):
Section "Monitor"
Identifier "Monitor0"
Modeline "1920x1080_60.00" 172.80 1920 2040 2248 2576 1080 1081 1084 1118 -HSync +Vsync
EndSection
Section "Device"
Identifier "LVSD"
Driver "fglrx" #Choose the driver used for this monitor
Option "Videoram" "65536"
Option "Cachelines" "1980"
EndSection
Section "Screen"
Identifier "Screen0"
Device "LVDS"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Depth 24
Modes "1920x1080_60.00" "1366x768"
EndSubSection
EndSection
This also could be related to the driver you’re using, there are other common drivers available like
Driver "fbdev"
Driver "vesa"
Driver "fglrx"
The fbdev driver supports all hardware where a framebuffer driver is available.
The vesa driver supports most VESA-compatible video cards. There are some known exceptions, and those should be listed here.
fglrx is a X.org(7x) driver for ATI (Mobility(TM)) RADEON® and (Mobility(TM)) FireGL(TM) based video cards. The driver provides hardware acceleration for 3D graphics and video playback. It includes support for dual displays, TV Output and as of version 8.21.7 also OpenGL 2.0 (GLSL).
Depending on which driver you choose, certain options/functionality/compatibility would be enabled or not, you could change the driver and test with the options you said would work.
Finally, you have hundreds of options here to play with X11.