I found a solution to the problem and now can start at my desired refresh rate of 75 hz, I think it can works for all other people, open nvidia-settings then go to X server Display configuration and click on tab X Screen then on MetaMode there are three buttons where the first open a menu containing all the possible resolution and refresh rate, take note of the string containing your desired settings the look at the image right above and by pressing the Delete button remove all the resolution and refresh rate you don't want leaving only the string you want, if you accidentally remove the desired string then use button Add to reinsert it in, finally apply the desired resolution and refresh rate and pressing Save to X configuration file button save in xorg.conf. Restart and it should works, if it doesn't look at my xorg.conf below when I modified the line
VertRefresh 55.0 - 75.0 in VertRefresh 75.0 - 75.0 to force the use of 75 hz and added line
Option "UseEDIDFreqs" "False" in section Screen to tell X to use only my settings. I hope it will help someone.
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 295.33 (buildd@zirconium) Fri Mar 30 13:38:49 UTC 2012
I found a solution to the problem and now can start at my desired refresh rate of 75 hz, I think it can works for all other people, open nvidia-settings then go to X server Display configuration and click on tab X Screen then on MetaMode there are three buttons where the first open a menu containing all the possible resolution and refresh rate, take note of the string containing your desired settings the look at the image right above and by pressing the Delete button remove all the resolution and refresh rate you don't want leaving only the string you want, if you accidentally remove the desired string then use button Add to reinsert it in, finally apply the desired resolution and refresh rate and pressing Save to X configuration file button save in xorg.conf. Restart and it should works, if it doesn't look at my xorg.conf below when I modified the line
VertRefresh 55.0 - 75.0 in VertRefresh 75.0 - 75.0 to force the use of 75 hz and added line
Option "UseEDIDFreqs" "False" in section Screen to tell X to use only my settings. I hope it will help someone.
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 295.33 (buildd@zirconium) Fri Mar 30 13:38:49 UTC 2012
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 "HannStar Display Corp Hanns.G HB171"
HorizSync 24.0 - 71.0
VertRefresh 75.0 - 75.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce 8400 GS"
Option "NoLogo" "True"
Option "AddARGBGLXVisuals" "True"
Option "AddARGBVisuals" "True"
Option "tripleBuffer" "True"
Option "BackingStore" "True"
Option "RenderAccel" "True"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "UseEDIDFreqs" "False"
Option "TwinView" "0"
Option "metamodes" "1440x900_75 +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection