Unclear Screen Nvidia on Debian

Hey everyone,

i have bought GM206 [GeForce GTX 960] and installed debian on my home pc (Dell XPS i5).

I have a WQHD monitor (Dell U2515) but the text is not clear as when i connect my laptop. I am afraid there is something missing or i have no idea, here are some pictures

https://postimg.org/image/pp101iuo7/

https://postimg.org/image/r5cijnxl3/

https://postimg.org/image/x7k5a5m13/

can anyone explain this or give me some help how to adjust the screen…even my eyes are hurting! On Windows … the screen is much better and comfortable

here are my settings:

±--------------------------------------- Xorg file --------------------------------------+

nvidia-settings: X configuration file generated by nvidia-settings

nvidia-settings: version 375.26 (buildd@debian) Mon Jan 16 21:27:31 UTC 2017

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”
# HorizSync source: edid, VertRefresh source: edid
Identifier “Monitor0”
VendorName “Unknown”
ModelName “DELL U2515H”
HorizSync 30.0 - 113.0
VertRefresh 56.0 - 86.0
Option “DPMS”
EndSection

Section “Device”
Identifier “Device0”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “GeForce GTX 960”
EndSection

Section “Screen”
Identifier “Screen0”
Device “Device0”
Monitor “Monitor0”
DefaultDepth 24
Option “Stereo” “0”
Option “metamodes” “2560x1440_60 +0+0”
Option “SLI” “Off”
Option “MultiGPU” “Off”
Option “BaseMosaic” “off”
SubSection “Display”
Depth 24
EndSubSection
EndSection

±--------------------------------------- nvidia settings --------------------------------------+

/home/arisen/.nvidia-settings-rc

Configuration file for nvidia-settings - the NVIDIA X Server Settings utility

Generated on Thu Feb 23 12:47:06 2017

ConfigProperties:

RcFileLocale = C
DisplayStatusBar = Yes
SliderTextEntries = Yes
IncludeDisplayNameInConfigFile = No
ShowQuitDialog = Yes
UpdateRulesOnProfileNameChange = Yes
Timer = Memory_Used_(GPU_0),Yes,3000
Timer = Thermal_Monitor_(GPU_0),Yes,1000
Timer = PowerMizer_Monitor_(GPU_0),Yes,1000

Attributes:

0/SyncToVBlank=1
0/LogAniso=0
0/FSAA=0
0/TextureClamping=1
0/FXAA=1
0/AllowFlipping=1
0/FSAAAppControlled=1
0/LogAnisoAppControlled=1
0/OpenGLImageSettings=3
0/FSAAAppEnhanced=0
0/XVideoSyncToDisplayID=DP-0
[DPY:DVI-I-0]/Dithering=0
[DPY:DVI-I-0]/DitheringMode=0
[DPY:DVI-I-0]/DitheringDepth=0
[DPY:DVI-I-0]/SynchronousPaletteUpdates=0
[DPY:DVI-I-1]/Dithering=0
[DPY:DVI-I-1]/DitheringMode=0
[DPY:DVI-I-1]/DitheringDepth=0
[DPY:DVI-I-1]/ColorSpace=0
[DPY:DVI-I-1]/ColorRange=0
[DPY:DVI-I-1]/SynchronousPaletteUpdates=0
[DPY:HDMI-0]/Dithering=0
[DPY:HDMI-0]/DitheringMode=0
[DPY:HDMI-0]/DitheringDepth=0
[DPY:HDMI-0]/ColorSpace=0
[DPY:HDMI-0]/ColorRange=0
[DPY:HDMI-0]/SynchronousPaletteUpdates=0
[DPY:DP-0]/RedBrightness=0.000000
[DPY:DP-0]/GreenBrightness=0.000000
[DPY:DP-0]/BlueBrightness=0.000000
[DPY:DP-0]/RedContrast=0.000000
[DPY:DP-0]/GreenContrast=0.000000
[DPY:DP-0]/BlueContrast=0.000000
[DPY:DP-0]/RedGamma=1.090000
[DPY:DP-0]/GreenGamma=1.090000
[DPY:DP-0]/BlueGamma=1.090000
[DPY:DP-0]/Dithering=0
[DPY:DP-0]/DitheringMode=0
[DPY:DP-0]/DitheringDepth=0
[DPY:DP-0]/DigitalVibrance=0
[DPY:DP-0]/ColorSpace=0
[DPY:DP-0]/ColorRange=0
[DPY:DP-0]/SynchronousPaletteUpdates=0
[DPY:DP-1]/Dithering=0
[DPY:DP-1]/DitheringMode=0
[DPY:DP-1]/DitheringDepth=0
[DPY:DP-1]/ColorSpace=0
[DPY:DP-1]/ColorRange=0
[DPY:DP-1]/SynchronousPaletteUpdates=0
[DPY:DP-2]/Dithering=0
[DPY:DP-2]/DitheringMode=0
[DPY:DP-2]/DitheringDepth=0
[DPY:DP-2]/ColorSpace=0
[DPY:DP-2]/ColorRange=0
[DPY:DP-2]/SynchronousPaletteUpdates=0
[DPY:DP-3]/Dithering=0
[DPY:DP-3]/DitheringMode=0
[DPY:DP-3]/DitheringDepth=0
[DPY:DP-3]/ColorSpace=0
[DPY:DP-3]/ColorRange=0
[DPY:DP-3]/SynchronousPaletteUpdates=0
[DPY:DP-4]/Dithering=0
[DPY:DP-4]/DitheringMode=0
[DPY:DP-4]/DitheringDepth=0
[DPY:DP-4]/ColorSpace=0
[DPY:DP-4]/ColorRange=0
[DPY:DP-4]/SynchronousPaletteUpdates=0
[DPY:DP-5]/Dithering=0
[DPY:DP-5]/DitheringMode=0
[DPY:DP-5]/DitheringDepth=0
[DPY:DP-5]/ColorSpace=0
[DPY:DP-5]/ColorRange=0
[DPY:DP-5]/SynchronousPaletteUpdates=0