това което е по-долу е моят xorg.conf. С две карти съм. първата е AGP nvidia 6600 а втората е PCI ati /4mb. Може да видиш как съм ги конфигурирал. Само че е малко по-различно (да не те заблудя нещо). Голямата карта (AGP) си изкарва сигнала на Монитор -CTX, а малката (PCI) конфигурирана да изкарва сигнал на Телевизор през SCART букса. В това няма нищо различно (това НЕ Е tv-out). Просто телевизора се използва като втори монитор, който е настроен и може да работи само на един режим 50Hz 720x540. Не обръщай внимание на редовете  ModeLine   "PAL-min" 14.125 .... - изтрий си ги.
Това което при тебе би могло да е от проблем е на втория/стар монитор да му зададеш по малки стойности на  
HorizSync   8-75
VertRefresh 20-60
или нещо такова, за да може X-a да пусне режим с по-малка честота на опресняване към монитора и монитора да може да я изкара. Трябва да пробваш с различни стойности докато го уцелиш.
Друг проблем, който се сещам е в секциата 'Моdule'  редовете
#       Load        "glx"   # libglx.a
#       Load        "dri"   # libdri.a
съм ги забранил. Стават неприятни работи, ако първата карта подържа правилно glx, a пък втората няма? ами като се с от различни производители. glx на nvidia и glx на ATI? GlX-a май е глобален за X-a. Даже мислех да пускам питане тук в linux-bg, как може да се задава   GLX на всеки Device по отделно? И изобщо възможно ли е това с карти от различни производители.
Е на мен това ми е проблема. Не мога да си играя на UT2004 и едновреммено да гледам филм на втория монитор.....  
| Примерен код  | 
 # ********************************************************************** # Refer to the XF86Config(4/5) man page for details about the format of # this file. # **********************************************************************
 
  Section "dri"         # Access to OpenGL ICD is allowed for all users:         Mode 0666         # Access to OpenGL ICD is restricted to a specific user group:         #    Group 100    # users         #    Mode 0660 EndSection
  Section "Module"     Load        "dbe"   # Double buffer extension
      SubSection  "extmod"       Option    "omit xfree86-dga"   # don't initialise the DGA extension     EndSubSection
 
      Load        "type1"     Load        "freetype"
 
  #       Load        "glx"   # libglx.a #       Load        "dri"   # libdri.a EndSection
  # ********************************************************************** # Files section.  This allows default font and rgb paths to be set # **********************************************************************
  Section "Files"     RgbPath     "/usr/X11R6/lib/X11/rgb"
  #   FontPath   "/usr/X11R6/lib/X11/fonts/local/"     FontPath   "/usr/X11R6/lib/X11/fonts/misc/:unscaled"     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/X11R6/lib/X11/fonts/75dpi/" #   FontPath   "/usr/X11R6/lib/X11/fonts/100dpi/" ###add by my fixed######### FontPath   "/usr/share/CyrFont/75dpi:unscaled" FontPath   "/usr/share/CyrFont/100dpi:unscaled" FontPath   "/usr/share/CyrFont/misc:unscaled" FontPath   "/usr/share/CyrFont/Xfonts:unscaled" ###add by my PS######### FontPath  "/usr/share/CyrFont/ADOBE" FontPath  "/usr/share/CyrFont/ADOBE-WinFont-1251" FontPath "unix/:7100"
  # The module search path.  The default path is shown here. #    ModulePath "/usr/X11R6/lib/modules" EndSection
  # ********************************************************************** # Server flags section. # ********************************************************************** Section "ServerFlags"
  # Uncomment this to cause a core dump at the spot where a signal is # received.  This may leave the console in an unusable state, but may # provide a better stack trace in the core dump to aid in debugging
  #    Option "NoTrapSignals"
  # Uncomment this to disable the <Crtl><Alt><BS> server abort sequence # This allows clients to receive this key event.
  #    Option "DontZap"
  # Uncomment this to disable the <Crtl><Alt><KP_+>/<KP_-> mode switching # sequences.  This allows clients to receive these key events.
  #    Option "Dont Zoom"
  # Uncomment this to disable tuning with the xvidtune client. With # it the client can still run and fetch card and monitor attributes, # but it will not be allowed to change them. If it tries it will # receive a protocol error.
  #    Option "DisableVidModeExtension"
  # Uncomment this to enable the use of a non-local xvidtune client.
  #    Option "AllowNonLocalXvidtune"
  # Uncomment this to disable dynamically modifying the input device # (mouse and keyboard) settings.
  #    Option "DisableModInDev"
  # Uncomment this to enable the use of a non-local client to # change the keyboard or mouse settings (currently only xset).
  #    Option "AllowNonLocalModInDev" EndSection
  # ********************************************************************** # Input devices # **********************************************************************
  # ********************************************************************** # Core keyboard's InputDevice section # **********************************************************************
  Section "InputDevice"     Identifier  "Keyboard1"     Driver      "keyboard"     #Driver     "kbd"     Option "Xleds" "1 2 3"     Option "AutoRepeat" "500 30"     Option "XkbModel"   "pc101"     Option "XkbLayout"  "bg_st" #   Option "XkbVariant" "BDS"     Option "XkbVariant" "phonetic"     Option "XkbOptions" "grp:ctrl_shift_toggle,grp_led:scroll,altwin:meta_alt" EndSection
 
  Section "InputDevice"     Identifier  "Keyboard2"     Driver      "kbd"     Option "Device"      "/dev/zero"     Option "AutoRepeat" "500 30"     Option "XkbModel"   "pc101"     Option "XkbLayout"  "bg_st"     Option "XkbVariant" "phonetic"     Option "XkbOptions" "grp:ctrl_shift_toggle,grp_led:scroll,altwin:meta_alt" EndSection
 
  Section "InputDevice"         Identifier  "Mouse1"         Driver      "mouse" #        Option      "Device" "/dev/usb/mouse0"          Option      "Device" "/dev/input/mice" #        Option      "Device" "/dev/input/mouse0"
          Option      "Protocol" "IMPS/2"         Option      "Emulate3Buttons" "on"         Option      "ZAxisMapping" "4 5" EndSection
 
  Section "InputDevice"     Identifier  "Mouse2"     Driver      "mouse"     Option "Protocol"    "PS/2"     Option "Device"      "/dev/mouse"     Option "Emulate3Buttons" EndSection
 
 
 
  Section "Monitor"     Identifier  "CTX" # sledwashtia red raboti bez GATOS draiveri #   HorizSync   30 - 110 # sledwashtia red raboti SAS GATOS draiveri #    HorizSync   31.5 - 75.5
       HorizSync   30 - 110.0 #     VertRefresh 30 - 110.0
  #    HorizSync  30-64         # multisync #    HorizSync  31.5, 35.2    # multiple fixed sync frequencies #    HorizSync  15-25, 30-50  # multiple ranges of sync frequencies
  # sledwashtia red raboti bez GATOS draiveri     VertRefresh 50-150 #    NVIDIA LINE #     ModeLine "800x600"  68  800  832  896 1048 600 601 604 631 -hsync +vsync
  #     ModeLine "800x600" 56.30 800 832 896 1048 600 601 604 631 +hsync +vsync #      ModeLine "800x600" 66.5 800 832 896 1048 600 601 604 631 -hsync +vsync
  #      ModeLine "1024x768"  94.50 1024 1072 1168 1376 768 769 772 808 -hsync +vsync
 
  EndSection
  Section "Monitor"     Identifier  "TV" #    HorizSync   8 - 37.3 #    VertRefresh 20 - 800
      HorizSync   8-75     VertRefresh 20-800
  #    HorizSync   8 - 20 #    VertRefresh 20 - 60 #from auto mode 85hz
 
  #ATI nadolu bez Vsync #       ModeLine "800x600" 66.5 800 832 896 1048 600 601 604 631 -hsync +vsync         ModeLine "1024x768"  94.50 1024 1072 1168 1376 768 769 772 808 -hsync +vsync         ModeLine   "PAL-max" 14.125  768 772 836 904 576 578 581 625 -hsync +vsync Interlace         ModeLine   "PAL-min" 14.125  720 744 808 904 540 558 561 625 -hsync +vsync Interlace     Gamma 0.45     Option "Composite_sync" "off" EndSection
 
  Section "Device"     Identifier  "ATI-match"     VendorName  "Unknown"     BoardName   "Unknown"     Driver     "ati"     BusID      "PCI:2:1:0" #gresho-disable #    BusID      "PCI:2:3:0"
  EndSection
  Section "Device"     Identifier  "radeon"     VendorName  "Unknown"     BoardName   "Unknown"     #driver      "nv"     #Driver     "vesa"     Driver     "nvidia"     #Option "LoadKernelModule" "off"
      #Used to prevent flickering or tearing problem caused by display buffer underflow.     #AUTO   -- Driver calculated (default).     #BIOS   -- Remain unchanged from BIOS setting. Use this if the calculation is not correct for your card.     #HIGH   -- Force to the highest priority. Use this if you have problem with above options. This may affect performence slightly.     #Option "DisplayPriority" "BIOS"     BusID      "PCI:1:0:0"     #Option "NoAccel" "on" EndSection
 
 
  # ********************************************************************** # Screen sections # **********************************************************************
  Section "Screen"     Identifier  "Screen1"     Device      "radeon"     Monitor     "CTX"     DefaultDepth 24
      Subsection "Display"         Depth       8         Modes       "800x600" "1024x768" "1280x1024"         ViewPort    0 0     EndSubsection     Subsection "Display"         Depth       16         Modes       "1280x1024" "1024x768" "800x600"         ViewPort    0 0     EndSubsection     Subsection "Display"         Depth       24         Modes       "1280x1024" "1024x768" "800x600"         ViewPort    0 0     EndSubsection EndSection
  Section "Screen"     Identifier  "Screen2"     Device      "ATI-match"     Monitor     "TV"     DefaultDepth 24
      Subsection "Display"         Depth       8         Modes       "PAL-min"         ViewPort    0 0     EndSubsection     Subsection "Display"         Depth       16         Modes       "PAL-min"         ViewPort    0 0     EndSubsection     Subsection "Display"         Depth       24         Modes       "PAL-min"         ViewPort    0 0     EndSubsection EndSection
  # ********************************************************************** # ServerLayout sections. # **********************************************************************
 
  Section "ServerLayout"     Identifier  "Layout1"
      Screen "Screen1"    Screen "Screen2" rightof "Screen1"
      InputDevice "Mouse1" "CorePointer"     InputDevice "Mouse2" "AlwaysCore" #   InputDevice "Mouse2" "CorePointer"     InputDevice "Keyboard1" "CoreKeyboard" Option "AllowMouseOpenFail" "true" EndSection
  Section "ServerLayout"     Identifier  "Layout2"     Screen "Screen2"
     InputDevice "Mouse1" "CorePointer"    InputDevice "Keyboard1" "CoreKeyboard" EndSection
  [naka@P2 X11]$
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