non ti so aiutare su yast o altri tool di X, io ci ho smenato un po' andando a modificare a manina il file di config; che scheda video hai? questo è il mio XF86Config per la ati:

codice:
Section "dri"
    Mode 0666
EndSection

Section "Module"
    Load        "dbe"  	# Double buffer extension
    SubSection  "extmod"
    EndSubSection
    Load        "type1"
    Load        "freetype"
    Load        "glx"   # libglx.a
    Load        "dri"   # libdri.a
EndSection

Section "Files"
    RgbPath	"/usr/X11R6/lib/X11/rgb"
    FontPath 	"/usr/X11R6/lib/X11/fonts/misc"
    FontPath 	"/usr/X11R6/lib/X11/fonts/75dpi:unscaled"
    FontPath 	"/usr/X11R6/lib/X11/fonts/100dpi:unscaled"
    FontPath 	"/usr/X11R6/lib/X11/fonts/Type1"
    FontPath 	"/usr/X11R6/lib/X11/fonts/Speedo"
    FontPath 	"/usr/local/share/fonts"
    FontPath 	"/usr/share/fonts"
    FontPath 	"/usr/X11R6/lib/X11/fonts"
    FontPath 	"/usr/lib/X11/fonts/misc"
    FontPath 	"/usr/lib/X11/fonts/cyrillic"
    FontPath 	"/usr/lib/X11/fonts/100dpi"
    FontPath 	"/usr/lib/X11/fonts/75dpi"
    FontPath 	"/usr/lib/X11/fonts/Type1"
    FontPath 	"/usr/lib/X11/fonts/Speedo"
    FontPath 	"/usr/share/fonts/afms"
    FontPath 	"/usr/share/fonts/truetype"
    FontPath 	"/usr/share/fonts/type1"
    FontPath 	"/usr/X11R6/lib/X11/fonts/cyrillic"
    FontPath 	"/usr/X11R6/lib/X11/fonts/TrueType"
EndSection

Section "InputDevice"
    Identifier	"Keyboard1"
    Driver	"Keyboard"
    Option "AutoRepeat"	"500 30"
    Option "XkbRules"	"xfree86"
    Option "XkbModel"	"pc101"
    Option "XkbLayout"	"us"
EndSection

Section "InputDevice"
    Identifier	"Mouse1"
    Driver "mouse"
    Option "Corepointer"
    Option "SendCoreEvents"	"true"
    Option "Protocol"   "ImPS/2"
    Option "ZAxisMapping"   "4 5"
    Option "Device"     "/dev/input/mice"
EndSection

Section "Monitor"
    Identifier  "Monitor0"
    HorizSync   30-94
    VertRefresh 48-120
    Option "DPMS"
EndSection

Section "Monitor"
    Identifier  "Monitor1"
    HorizSync   30-96
    VertRefresh 50-160
    Option "DPMS"
EndSection

Section "Device"
    Identifier			"ATI0"
    Driver			"fglrx"
    Option "AGPMode"		"4"
    Option "no_accel"		"no"
    Option "no_dri"		"no"
    Option "mtrr"		"off" 
    Option "DesktopSetup"	"0x00000000" 
    Option "MonitorLayout"	"AUTO,AUTO"
    Option "IgnoreEDID"		"off"
    Option "HSync2"		"30-96" 
    Option "VRefresh2"		"50-160" 
    Option "ScreenOverlap"	"0" 
    Option "NoTV"		"yes"     
    Option "TVStandard"		"NTSC-M"     
    Option "TVHSizeAdj"		"0"     
    Option "TVVSizeAdj"		"0"     
    Option "TVHPosAdj"		"0"     
    Option "TVVPosAdj"		"0"     
    Option "TVHStartAdj"		"0"     
    Option "TVColorAdj"		"0"     
    Option "GammaCorrectionI"	"0x00000000"
    Option "GammaCorrectionII"	"0x00000000"
    Option "Capabilities"		"0x00000000"
    Option "VideoOverlay"		"on"
    Option "OpenGLOverlay"		"off"
    Option "CenterMode"		"off"
    Option "PseudoColorVisuals"	"off"
    Option "Stereo"		"off"
    Option "StereoSyncEnable"	"1"
    Option "FSAAEnable"		"no"
    Option "FSAAScale"		"1"
    Option "FSAADisableGamma"	"no"
    Option "FSAACustomizeMSPos"	"no"
    Option "FSAAMSPosX0"		"0.000000"
    Option "FSAAMSPosY0"		"0.000000"
    Option "FSAAMSPosX1"		"0.000000"
    Option "FSAAMSPosY1"		"0.000000"
    Option "FSAAMSPosX2"		"0.000000"
    Option "FSAAMSPosY2"		"0.000000"
    Option "FSAAMSPosX3"		"0.000000"
    Option "FSAAMSPosY3"		"0.000000"
    Option "FSAAMSPosX4"		"0.000000"
    Option "FSAAMSPosY4"		"0.000000"
    Option "FSAAMSPosX5"		"0.000000"
    Option "FSAAMSPosY5"		"0.000000"
    Option "UseFastTLS"		"0"
    Option "BlockSignalsOnLock"	"on"
    Option "UseInternalAGPGART"	"no"
    Option "ForceGenericCPU"	"no"
    BusID "PCI:1:0:0"
    Screen 0
EndSection

Section "Device"
    Identifier                          "ATI1"
    Driver                              "fglrx"
    Option "DesktopSetup"               "0x00000000"
    Option "FSAAEnable"                 "no"
    Option "FSAAScale"                  "1"
    Option "FSAADisableGamma"           "no"
    Option "FSAACustomizeMSPos"         "no"
    Option "FSAAMSPosX0"                "0.000000"
    Option "FSAAMSPosY0"                "0.000000"
    Option "FSAAMSPosX1"                "0.000000"
    Option "FSAAMSPosY1"                "0.000000"
    Option "FSAAMSPosX2"                "0.000000"
    Option "FSAAMSPosY2"                "0.000000"
    Option "FSAAMSPosX3"                "0.000000"
    Option "FSAAMSPosY3"                "0.000000"
    Option "FSAAMSPosX4"                "0.000000"
    Option "FSAAMSPosY4"                "0.000000"
    Option "FSAAMSPosX5"                "0.000000"
    Option "FSAAMSPosY5"                "0.000000"
    BusID "PCI:1:0:0"
    Screen 1
EndSection

Section "Screen"
    Identifier  "Screen0"
    Device      "ATI0"
    Monitor     "Monitor0"
    DefaultDepth 24
    Subsection "Display"
        Depth       24
        Modes       "1280x1024"
        ViewPort    0 0 
    EndSubsection
EndSection

Section "Screen"
    Identifier  "Screen1"
    Device      "ATI1"
    Monitor     "Monitor1"
    DefaultDepth 24
    Subsection "Display"
        Depth       24
        Modes       "1280x1024"
        ViewPort    0 0 
    EndSubsection
EndSection

Section "ServerLayout"
    Identifier  "Server Layout"
    Screen "Screen0"
    Screen "Screen1" LeftOf "Screen0"
    InputDevice "Mouse1" "CorePointer"
    InputDevice "Keyboard1" "CoreKeyboard"
EndSection