FSX: full screen issue with matrox TH

Hello
I have somequestions regarding the use of FSX in full screen mode with a Matrox TH card and two other monitors. (See photo 1)

http://2.bp.blogspot.com/-RrwWBQs_cZ...0/DSC_0276.jpg
Photo 1
Far
left: main tower PC Zalman machine assembled by PRENIUM PC (very
good!), next COMPAQ laptop (PC2) and the extreme right an assembled
PC (PC3): see below configuration)

I am currently in windowed mode, but I'm a little disappointed by the performance of FSX (in terms of FPS: average 20, 18.5 if I give up SLI) due to the
machine that I put behind .... but I read that the full screen mode is less demanding

Switching to windowed mode make unusable screens 2 and 3 of the Matrox (see photo 2). In addition, the new display views remains confined to my main display (ASUS screen ... see description below).
http://1.bp.blogspot.com/-NtfIr9zYZO...0/DSC_0277.jpg
Photo 2


In addition I will soon bring in the VRInsight CDU II which will also propably cause problem of full screen (I just return the CDU OpenCockpits is falsely sold as compatible with FSX PMDG 747 ...)
What is the procedure/tricks/cfg edition knowing that the expected output is as follows:


http://1.bp.blogspot.com/-sV74YHt_rL...U+MATROX+1.JPG

• Main Display:
  Monitor 1 (display 2): ASUS VW1925+ (1680x1050) on DVI / VGA
  connector - INSTRUMENTS (and future CDU II)
• Matrox MTH2Go: Monitors
  2 (display 1): 3x PHILIPS Brillance231B 24 inches (but limited to
  1680x1050x3) control bezel works well, brings all 3 22 inches, not
  annoying) on ​​DVI TO VIEW OUTSIDE COCKPIT
• Monitor 3 (display3)
  ViewSonic VA2216w (1680x1050) on USB-DVI-VGA converter - FOR
  OVERHEAD PANEL
  
  
  Both cards are NVIDIA SLI (only connectors on the map above are functional, hence the use of
  USB adapter) - Driver Updated
  
  Thank you for your advice
  
  Philippe
  --------------------------------------------------
  CONFIGURATION:
  
  MAIN
  PC
  Internal components
  Gigabyte X79-UD3
  Intel Core
  i7-3930K
  Water-cooling System Cooler Master Seidon 120M
  16GoDDR3
  pc17000 2133MHz G.Skill RipjawsX Gaming series (in 4x4096) Dual /
  Quad-Channel
  2 x Nvidia Geforce GTX-760 OC-Edition 2GoDDR5
  (Gigabyte Windforce) in SLI
  7.1 The Creative X-Fi Xtreme Audio
  PCI-Express card
  Case Zalman Z11 USB3.0 + 3 more 120mm fans.
  Power
  Supply GX-750W Bronze Cooler Master.
  Samsung SSD 840 Series 250GB
  SATA III
  Hard Drive 1000GB SATA3-600 Western Digital Caviar Black
  64MB cache =
  LG 24x DVD Burner double layer s-ata
  Windows Seven
  Home Premium 64bit
  
  
  And software localization

• Primary PC: FSX PMDG
  747/FSUIPC, ACTIVE SKY 2012 - Hardware: Saitek Yoke PILOTPRO, 2x
  SAITEK THROTTLE QUADRANT SAITEK RADIO PANEL CP FLIGHT MCP, CH
  PROPEDALS
• PC2 (Windows Seven Home
  Premium 64bit) Squawkbox, Flightcommander, Topcat, Navigraph
• PC3 (Vista Ultimate 64
  ... nicely working for the last 7 years ....) and miscellaneous
  Vatspy

and obviously Input Director on each machine