Farbtiefe unter Ubuntu 15.10 einstellen

Hallo,

hab folgendes Problem. Mein System ist nur auf 24 bit Farbtiefe eingestellt und installiert sind Nvidia Prop. Treiber.
Weder in den nvidia-settings noch in den Ubuntu Einstellungen lässt sich irgendwo die Farbtiefe einstellen. Der Treiber hat eine xorg angelegt in der ich ja eigentlich manuell die 32 reinschreiben könnte...

Trotzdem muss da doch was auch "eleganter" zu lösen zu sein.

System selbst

Nvidia GTX 970
+
27" 3K Monitor

Code:

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# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 352.21  (buildd@lgw01-37)  Thu Jul 23 11:50:49 UTC 2015

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 352.63  (buildmeister@swio-display-x64-rhel04-11)  Sat Nov  7 22:00:19 PST 2015

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

Section "Files"
EndSection

Section "InputDevice"

    # generated from default
    Identifier    "Mouse0"
    Driver        "mouse"
    Option        "Protocol" "auto"
    Option        "Device" "/dev/psaux"
    Option        "Emulate3Buttons" "no"
    Option        "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"

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

Section "Monitor"
    Identifier    "Monitor0"
    VendorName    "Unknown"
    ModelName      "Ancor Communications Inc ASUS PB278"
    HorizSync      24.0 - 99.0
    VertRefresh    24.0 - 76.0
    Option        "DPMS"
EndSection

Section "Device"
    Identifier    "Device0"
    Driver        "nvidia"
    VendorName    "NVIDIA Corporation"
    BoardName      "GeForce GTX 970"
EndSection

Section "Screen"
    Identifier    "Screen0"
    Device        "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option        "Stereo" "0"
    Option        "nvidiaXineramaInfoOrder" "DFP-2"
    Option        "metamodes" "nvidia-auto-select +0+0"
    Option        "SLI" "Off"
    Option        "MultiGPU" "Off"
    Option        "BaseMosaic" "off"
    SubSection    "Display"
        Depth      24
    EndSubSection
EndSection

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(mehr HW Infos sollten eher unwichtig sein).