Monitor Screen Width

I have installed the nVidia driver for my card and added a custom resolutin: 1440x900 wich is my monitor native resolution and the screen does not fit the width of the monitor only about 75%

Here is my xorg.conf

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 340.93  (buildmeister@swio-display-x86-rhel47-03)  Wed Aug 19 17:11:04 PDT 2015

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from data in "/etc/sysconfig/mouse"
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "IMPS/2"
    Option         "Device" "/dev/input/mice"
    Option         "Emulate3Buttons" "yes"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"

    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "CRT-1"
    HorizSync       55.0 - 83.0
    VertRefresh     50.0 - 75.0
    ModeLine       "1440x900_60.00" 119.00 1440 1696 1864 2128 900 901 904 932 -hsync +vsync
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection


Any idea what might cause this ?