J'ai lu les differents post sur le sujet et j'ai ete amene a essaye:
xvidtune (g rien compris et marche pas)
edit du xf86config4 le voici et ca me donne rien :
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Section "Files"
# Multiple FontPath entries are allowed (they are concatenated together)
# By default, Mandrake 6.0 and later now use a font server independent of
# the X server to render fonts.
FontPath "unix/:-1"
EndSection
Section "ServerFlags"
#DontZap # disable <Crtl><Alt><BS> (server abort)
#DontZoom # disable <Crtl><Alt><KP_+>/<KP_-> (resolution switching)
AllowMouseOpenFail # allows the server to start up even if the mouse doesn't work
EndSection
Section "Module"
Load "dbe" # Double-Buffering Extension
Load "v4l" # Video for Linux
Load "extmod"
Load "type1"
Load "freetype"
Load "glx" # 3D layer
EndSection
Section "InputDevice"
Identifier "Keyboard1"
Driver "Keyboard"
Option "XkbModel" "pc105"
Option "XkbLayout" "fr"
Option "XkbOptions" ""
EndSection
Section "InputDevice"
Identifier "Mouse1"
Driver "mouse"
Option "Protocol" "ExplorerPS/2"
Option "Device" "/dev/usbmouse"
Option "ZAxisMapping" "6 7"
EndSection
Section "Monitor"
Identifier "monitor1"
VendorName "Mitsubishi"
ModelName "Mitsubishi Diamond Plus 91 (NFL9905)"
HorizSync 30.0-96.0
VertRefresh 50.0-140.0
ModeLine "640x480" 65.22 640 672 832 896 480 482 494 520
ModeLine "800x600" 100.35 800 840 1040 1120 600 602 614 640
ModeLine "1024x768" 134.24 1024 1072 1312 1408 768 770 782 808
ModeLine "1152x864" 147.18 1152 1200 1440 1536 864 866 878 904
ModeLine "1280x960" 165.88 1280 1336 1616 1728 960 962 974 1000
EndSection
Section "Device"
Identifier "device1"
VendorName "NVidia"
BoardName "NVIDIA GeForce (fbdev)"
Driver "fbdev"
Option "DPMS"
EndSection
Section "Screen"
Identifier "screen1"
Device "device1"
Monitor "monitor1"
DefaultColorDepth 16
Subsection "Display"
Depth 8
Modes "1280x960"
EndSubsection
Subsection "Display"
Depth 15
Modes "1280x960"
EndSubsection
Subsection "Display"
Depth 16
Modes "1280x960"
EndSubsection
Subsection "Display"
Depth 24
Modes "1280x960"
EndSubsection
EndSection
Section "ServerLayout"
Identifier "layout1"
InputDevice "Keyboard1" "CoreKeyboard"
InputDevice "Mouse1" "CorePointer"
Screen "screen1"
EndSection
J'attends vos suggestion avec impatience car c trop moche le 60hz 
