Stretching a PowerPoint presentation across the desktop

1. select File\Page Setup from the menu and adjust the slide width so that the slide covers the whole desktop. For example with 2 monitors side by side, you would need to double the slide width, with 3 monitors triple it
2. stretch the slideshow window across the desktop, for example with UltraMon (using a 'maximize to desktop' hotkey)

Multi-monitor modes
Windows supports a single multi-monitor mode, usually referred to as standard or extended desktop mode, also DualView or independent displays mode.

In this mode, all monitors connected to the installed video cards form a single desktop, you can move the mouse and applications to any monitor. Each monitor can use different settings (resolution, color depth and refresh rate).

Most multi-monitor video cards (video cards which can drive 2 or more monitors) support additional, video card-specific modes.

Very common is clone mode: in this mode, the same image is shown on 2 or more monitors. Clone mode is usually limited to the monitors connected to a single video card, for example you couldn't clone monitor 1 (on video card 1) on monitor 3 (on video card 2) if you have two dualhead cards installed.

Span mode (also called stretched mode): in this mode, all the monitors connected to a single video card form a single large monitor. Windows thinks that you are using a single monitor instead of 2 or more, and each monitor needs to use the same resolution and color depth settings, and usually also the same refresh rate.
This mode is mainly useful for forcing applications which have no native multi-monitor support to use all available monitors. For example most games will only run on the primary monitor, and in span mode all monitors form a single large primary monitor.
When using span mode, Display Properties will usually show the primary monitor running at a widescreen resolution, for example 2048x768 (2 monitors at 1024x768 each), with the secondary monitor disabled.

To enable video card-specific multi-monitor modes, you usually need to disable the secondary monitor(s) connected to the video card, then open advanced display properties for the primary monitor, select the video card manufacturer's custom settings tab and select the multi-monitor mode you want to use.

For more on the multi-monitor modes supported by the various video card manufacturers, take a look at one of the following reviews: ATI review, Matrox review, Nvidia review.

When playing a video, it is also shown fullscreen on the other monitor
This happens if the video mirroring feature of your video card is enabled. You can disable this option on the tab for your video card under advanced display properties, Nvidia calls this feature Full Screen Video, for ATI video cards it is called theater mode, and Matrox calls it PureVideo/DVDMax.

Maximum number of monitors
The maximum number of monitors isn't known, but the often-cited limit of 10 monitors on Windows 2000/XP is only a limitation of the Display Properties applet, not the system as a whole. So installing more than 10 monitors should work fine, but you would need a custom application, for example UltraMon, to configure them. See this newsgroup thread for more information.

I have tested a 12-monitor Windows XP system with 3 Matrox G450 MMS quad cards, using UltraMon for configuration. Colorgraphic has built a 16-monitor system with Xentera GT cards, and expects to be able to run up to 64 monitors: see this thread and this thread for more information.

Secondary screen shifts when playing game
If your secondary monitor is to the right of the primary monitor, and you play a game which changes the resolution of the primary monitor, the windows on the secondary monitor will be shifted to the edge of the monitor. This is an issue with DirectX. Workarounds:

• make the primary monitor the right-most monitor before playing the game
• change the display resolution manually before playing the game

Distorted sound
When using some applications (for example a video player) on your secondary monitor(s), you might get distorted sound. This seems to be an issue with PCI bus bandwidth, see the following forum threads for more information: Really bad audio, Sounds when moving windows between monitors, Scratchy sound.

Nvidia dualhead cards
Dualhead is only supported by some GeForce2 MX, GeForce4 MX and GeForce4 Ti cards. Other Nvidia cards (for example GeForce3) do not support dualhead.

Additional points to consider when looking for an Nvidia card that supports 2 monitors/LCD flat panels:

• some cards are advertised as nView or TwinView capable, but only support a TV as secondary display. These cards usually have a single VGA port and TV-out
• some cards have both a VGA and a DVI connector, but don't support use of both connectors at the same time
• some cards have a DVI-D (digital only) connector instead of DVI-I (digital/analog), which means that a DVI-to-VGA converter will not work

Playing fullscreen video/DVD on secondary monitors
The following video players can play fullscreen on any monitor, and they stay in fullscreen mode when you work with a different application:

• NVDVD
• PowerDVD 4
• Winamp 5
• Windows Media Player 9
• Zoom Player

Multi-monitor KVM
A KVM (Keyboard Video Mouse) switch is used to control multiple computers using a single keyboard, mouse and monitor. A multi-monitor KVM serves the same purpose, but allows you to use multiple monitors.

If you have multiple computers but only use one at a time, a KVM allows you to share keyboard, mouse and monitors between the different systems, thereby saving you space and money.

The following drawing shows a sample scenario using 2 PCs, each with 2 video cards.

Available multi-monitor KVMs:

• Belkin OmniView SOHO Dual-Head
• CompuCable DUO-VGA KVM
• Dr. Bott MoniSwitchPro Dual VGA
• Guntermann & Drunck TripleMux
• Rose Electronics MultiVideo (available from KVM Switches Online)

Also see this thread in the forum for more on multi-monitor KVMs.

Dualhead cards and true multi-monitor support on Windows 2000
Due to a limitation in Windows 2000, dualhead cards that use a single chipset to drive both monitors require special workarounds in the driver to be properly recognized by the system. If these workarounds are not implemented, Windows 2000 sees a single large monitor instead of two.

This causes the following problems:

• using different resolutions for each monitor is not possible
• windows are maximized to the desktop instead of the monitor they are on, and dialog boxes appear centered on the desktop, split across monitors. Software included with the card may be used to work around these problems though
• taskbar is extended across both monitors instead of only a single one
• multi-monitor software will not work properly

All major video card/chipset manufacturers do now have Windows 2000 drivers with full multi-monitor support.

• Appian added support for their Hurricane cards, most likely also for other RADEON VE-based cards.
  
  
• ATI has added support for the RADEON 9xxx cards, but not for earlier cards. See this forum thread for more information.
  
  
• Matrox has supported this for a long time, when installing the drivers, make sure to enable support for independent displays.
  
  
• Nvidia added support in the 28.32 drivers, see this forum thread for more information.
  
  

Monitor calibration
Ideally, all monitors should have the same brightness, contrast and color temperature. There are 3 ways to calibrate a monitor:

Using monitor controls
All monitors have controls to adjust brightness and contrast, some also let you adjust colors. You can access the controls through buttons on the monitor or an on-screen menu.

Using monitor calibration features of the display driver
Most display drivers provided by the card or chipset manufacturer let you adjust brightness, contrast and color. To adjust these settings, open Display Properties, go to the monitor's advanced settings and look for an appropriately named tab.

Using special software
There are several tools available for monitor calibration, one that is readily available for download is PowerStrip. The advantage of a tool like this is that you can adjust all monitors from a single location, and you can create different monitor profiles, for example a brighter one for use at day, and a second for use at night.
For solid and repeatable results, a colorimeter (a tool to measure the display characteristics of a monitor) is recommended. The following packages include a colorimeter and calibration software: Spyder, ColorBlind Prove it!.

If you don't have a colorimeter, you can use a color chart to help with calibrating the monitors. See Star Systems' web page on color calibration for various charts and more information on the topic.

Unable to properly align monitors
I've had two reports from people using systems with 6 or more monitors, saying that it wasn't possible to properly align the monitors. Microsoft has confirmed this to be a problem in Windows 2000, a fix is planned for Service Pack 3.

"No buffer space available" error in TCP/IP applications
Check out this link for a solution: Windows 2000 exhausts PTEs with multiple monitors. Related information: WSAENOBUFS (10055) error.

Adding multi-monitor support to a Windows 98 driver set
First, locate a file in the system folder, vgartd.vxd. This file is used in every driver set that does support secondary monitors. The file is available from the Win98 SE CD, in DRIVERS\DISPLAY\MATROX\G200.

Next, copy the inf file and all the driver files that come on the install disk or CD of the card you want to use as second monitor. Make a folder on the harddrive and call it something like "second monitor", without the quotes. Put the drivers and inf file in this folder.

Next use notebook to open the inf file: look for a section that shows the primary drivers used on most systems; with my Number Nine Imagine 128 it was i128.drv, i128.dll, i128.vxd. On the next line after those make a blank line and type in vgartd.vxd.

Next, locate the addreg section of the particular device you are using (some inf files have info for more than one adapter). In the i128 inf file this section is called Imagine128.AddReg. In this section is where it tells the computer how to setup the device. Look for something like HKR,DEFAULT,drv,,i128.drv make a blank line after that line and copy that line to the blank line. Then change the second line to read something like HKR,DEFAULT,drv2,,i128.drv. Locate the minivdd line and do the same thing making it read minivdd2. This tells the computer that this adapter will be the second monitor.

Next, locate the section that says something like PCI\VEN and you should see the name given to the driver set. With my card it's called DeviceDesc="Number Nine Imagine 128". Add inside the quotes the word "multi" to rename it like a new driver set. Mine is renamed Number Nine Imagine 128 Multi.

Now it's time to install the drivers.

Special Note********* this so far only works until you reboot, then you have to reinstall the drivers each time. BUT, it's better than not being able to use the adapter at all.

That said, install the driver as you would any other, using "have disk" button to locate the folder we made to hold these files. Click on the inf file and load. When it asks for the location of the vgartd.vxd file browse to the Windows\System folder and open it, then click ok and ok. This will finish loading and initialize the second monitor. Follow instructions displayed on second monitor.

WARNING************ If it ask to reboot tell it no, because this isn't permanent. It have to be re-updated each time you reboot.

If you have questions or need help in doing this task, e-mail me at shade@xit.net.

Multimon on different operating systems

• Windows XP
• Windows 2000 and Beta 3 Preview
• Windows Me
• Linux
• Windows NT 4

Can I read my e-mail on the second monitor while playing a game?
This sounds great in theory, but usually doesn't work well. Here's why:

1. To use your e-mail or other program on the second monitor, you'll have to switch away from the game. Most games will minimize and pause when you do this.
2. If your second monitor is to the right of the primary monitor, there's another problem: if the game changes the display resolution, the applications on the second monitor will be moved partly off the monitor. The only workaround is to run the game at the same resolution as the Windows desktop.

Secondary card doesn't work with Windows 2000/XP
Try the following:

1. set the secondary card as primary in the BIOS. If you have an AGP and a PCI card, look for a BIOS setting that lets you select whether AGP or PCI should be initialized first (more information). If you have two PCI cards, you need to swap them
2. go to Display Properties, and set the card of your choice as primary. The primary card should be your better card, as it is the one that will have accelerated 3D graphics and will be used by games

This workaround should work fine with older S3 and ATI cards, which need to be booted as primary because they need access to the VGA BIOS. If you have more than one card with this requirement, you'll have to replace all but the first one as only one card can be primary in BIOS. See the shopping guide for some suggestions for secondary cards.

Here's what Steve Deng from Microsoft told me on the issue: 'Win2k doesn't support this card as secondary adapter because this s3 device needs to access vga registers and call int10. These behaviors conflict with the primary video adapter. Although there might be ways to hack the problem, Win2k doesn't implement those approaches.'

If the secondary card still doesn't work, you will need to make it primary in Windows as well.

Laptops
There are several ways to get multiple monitors with a laptop:

• using the second VGA output of the laptop
• adding a PCMCIA video card
• using a docking station with video card
• using a PCI video card in a PCMCIA-to-PCI expansion system
• adding an external video card
• using a second laptop or other PC as an additional monitor

Using the second VGA output of the laptop:
A lot of laptops have a VGA port for an external monitor, and by default the external monitor will show the same image as the built-in monitor. If the laptop has a video chipset with multi-monitor support (and the necessary drivers), you can choose to use the external monitor as a second monitor instead of a mirror of the built-in monitor.

• Windows XP: make sure you get the latest drivers, the default drivers may not have multi-monitor support
• Windows 2000: not all video chipsets will have drivers with multi-monitor support, newer ones most likely will though, for example Nvidia

Chipsets with multi-monitor support include: ATI MOBILITY RADEON, RAGE MOBILITY and RAGE LT PRO, NeoMagic MagicMedia 256AV, Nvidia GeForce Go and Quadro Go series, S3 Savage and ViRGE, Trident Cyber 9525DVD.

The following chipsets do not support multiple monitors: NeoMagic 128.

Adding a PCMCIA video card:
PCMCIA video cards are standard PCMCIA cards with a VGA or DVI output. You simply plug them into a PCMCIA slot, and instantly you have an additional monitor. These cards work fine with all versions of Windows (provided that drivers are available). See the Products page for a list of PCMCIA video cards.

Using a docking station with video card:
If your docking station supports it, you can add a standard PCI video card or a PCMCIA video card to get a second monitor. There are also docking stations with integrated video, for example the EasiDock 1000EV.
This should also work fine with all versions of Windows. Note that not all laptops support this, some will turn off the built-in monitor when they detect a video card in the docking station.
Please note: the EasiDock 5000 doesn't support video cards with PCI bridges (most quad video cards).

Using a PCI video card in a PCMCIA-to-PCI expansion system:
A PCI expansion system allows you to connect one or more PCI cards to your laptop via a PCMCIA card. Magma sells 1-4 slot PCI expansion systems for laptops. This should work fine with all versions of Windows.
Please note: the Matrox G200 MMS only works with Magma PCI expansion systems if bus mastering is disabled.

Adding an external video card:
The SideCar from Digital Tigers is a little box with a built-in video card which gets connected to a laptop using a PCMCIA card. Several models are available with support for 1-4 monitors, using video cards such as the Nvidia GeForceFX, ATI RADEON 9000 and Matrox G450 MMS. Depending on the model, DVI, VGA and TV-out are supported.

Using a second laptop or other PC as an additional monitor:
With MaxiVista, you can use a second laptop or desktop PC as an additional monitor. The second PC needs to be connected to the laptop via network, the main laptop needs to be running Windows 2000/XP or later. See the review for more information on MaxiVista.

Mirroring (same display on multiple monitors)
There is no built-in support for mirroring. Software solutions: UltraMon™ can do mirroring (on Windows 2000/XP only). Hardware solutions: a VGA splitter is a device that takes the video signal from one video card and sends it to multiple monitors. Each monitor has the same display. Here are some vendors: KVMs.com, NTI, National Technology. Simply do a search for 'vga splitter' to find more vendors.
Dualhead cards and laptop video chipsets usually have drivers with support for mirroring.

ATI video cards
After installing an ATI video card as secondary display adapter, you may get the following error message in Device Manager: 'Multiple Display Support cannot start on this device.' ATI has a solution to this problem: 3025.html.

TV tuner cards
Most video cards with TV tuners should be used as primary card, otherwise you will lose the TV tuner functionality.

TV cards from Hauppauge can show video on any monitor when using the WDM drivers. Please note that these cards may not work with all video cards, check their site for compatibility information.

ICQ on secondary monitor?
If you have version 2000 or later, use UltraMon™ to move the ICQ window. You won't be able to resize the window once it is on the secondary monitor, so position/size it as desired on the primary monitor first.
For earlier versions of ICQ, the following workaround can also be used: span the ICQ window over the primary monitor and the monitor where you want it, then simply resize it to the secondary monitor. Don't move the window after that, it will promptly snap back to the primary. This doesn't seem to work with monitors which are to the left of the primary monitor.

Alternatively, you could also use Trillian, an instant messaging client for multiple services, including ICQ. You may have to disable docking: Preferences > General > Contact List.

Does card x work as primary/secondary?
Take a look at the Compatibility Database to see if others are using your card successfully. In addition, check out Microsoft's Compatibility Lists, for Windows 98, Windows 2000 and Windows XP.

Changing the BIOS primary card
Look for a BIOS setting named 'Initialize First', 'Init Display First' or similar. In the Award BIOS, the setting is 'Init Display First' under 'Integrated Peripherals'. If your BIOS doesn't have such a setting, try to get an update. It is also possible that your BIOS always uses the AGP card as primary, this is the case with my Dell Precision 210.

When the setting is set to PCI, the first PCI video card found will be used as primary. This is the PCI video card in the lowest-numbered slot, the one nearest to the AGP slot.

On Windows 2000/XP, you can set any card as primary in Display Properties, but DOS applications will still use the BIOS primary display (boot display, the one which displayed BIOS settings during booting).

Desktop icons moving to primary monitor
If you have desktop icons on a secondary monitor, Windows will sometimes move them back to the primary monitor when you restart your system. The following multi-monitor utilities have a fix for this problem: Matrox PowerDesk, PowerStrip, UltraMon™. You can also use any other utility that can save/restore the position of desktop icons, for example EzDesk.

In addition, here's a manual fix for the problem, submitted by Cory:

1. Open Notepad and type the following:
   REGEDIT4
   
   [HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Desktop\Old WorkAreas]
   "NoOfOldWorkAreas"=dword:00000001
   
   
2. Save the file as "c:\icon.reg"
   
   
3. Open "c:\autoexec.bat" and type this at the very bottom of the file:
   regedit c:\icon.reg

High color cursor displayed in 256 colors
This happens if you don't use the same color depth for all monitors.

Multi-monitor desktop wallpapers
Use the wallpaper feature of UltraMon™ to create desktop wallpapers with a different background on each monitor, or a single background stretched across all monitors.

Other options:

Active Desktop: go to Control Panel, open Display and switch to the Web tab. Make sure the 'Show Web content' box is checked. Click 'New...' to add your image(s). You can stretch a single image across the whole desktop, or use a different image on each monitor.

Tiled background image: if your monitors are arranged horizontally in a single row, and the left-most monitor is the primary, you can span a single image across the whole desktop simply by tiling it. Open Display Properties > Background, select an image that is as large as your whole desktop, then choose Tile as the display mode. On Windows 98/Me, Active Desktop needs to be enabled for this to work.

HTML wallpaper: for a detailed how-to, see Brett's page.
Download multimon_wallpaper.zip for sample HTML wallpapers.

Here is a custom HTML wallpaper using multiple images:

Taskbar on second monitor?
UltraMon™ can add a taskbar to each monitor, see Smart Taskbar for more information.

If you want to move the Windows taskbar to a different monitor, make sure the taskbar is unlocked, then grab a free area on the taskbar with the mouse and drag it to the desired monitor. Additionally, you can also move individual toolbars (such as the Quick Launch or Address toolbar) to any monitor you like. To move a toolbar off the taskbar, grab it by its handle and drop it on a free area of the desktop. Toolbars can dock on any side of a monitor or float on the desktop.

You can also move the taskbar using the keyboard, very useful if it is on an inaccessible monitor (thanks go to Jeff Cornish):

1. press either the Windows key or Ctrl-Esc to pop the Start Menu up
2. press Esc to close it. The taskbar now has the focus
3. press Alt-Spacebar to pop the context menu for the taskbar
4. press M to trigger the 'move' function
5. use the arrow keys to move the cursor to another edge of the monitor(s) or press one of the arrow keys and then move the mouse. The Taskbar is now 'attached' to the end of the cursor, so moving the cursor near one of the monitor edges will snap the Taskbar there

You can also select 'Size' (S) instead of 'Move' to easily resize the Taskbar.

OpenGL hardware acceleration
See the OpenGL FAQ for detailed information.

DirectX hardware acceleration
Fullscreen applications are accelerated on any monitor, video overlays (using DirectShow) also. For DirectDraw and Direct3D applications running in a window, it depends on the DirectX version and the way they are programmed: prior to DirectX 8, windowed applications were never accelerated on secondary monitors. With DirectX 8, properly programmed applications will be fully accelerated on any monitor.

Games with multi-monitor support
There are only very few games with explicit multi-monitor support, some examples are Microsoft flight simulators and Star Trek: Armada II. Some games were released with dualhead support exclusively for Matrox cards, see Matrox enhanced games.

If a game has a windowed mode, it is usually possible to play it on multiple monitors either by placing additional views on secondary monitors, or stretching the game window across multiple monitors. You might have to use software rendering for this to work. For more information, see the gaming-related links.

Microsoft flight sims support putting additional views on secondary monitors. To put a view on a secondary monitor, choose 'Undock window' and move it to the desired position. Starting with Flight Simulator 2004, views on up to 4 monitors are hardware accelerated, previous versions only used hardware accelerated 3D on the primary monitor. See Multi-Monitor Support in Flight Simulator 2004 for more on this.

With dualhead video cards or the triplehead Matrox Parhelia (surround gaming), it is also possible to play some games stretched across all monitors by using a stretched (spanned) display mode. This way, the game sees a single wide monitor instead of 2 or 3 monitors (the game needs to support widescreen display modes). For more on surround gaming with the Matrox Parhelia, see the review.

For developers: Power Render by Egerter Software, a development kit for 3D games, has dualhead support. The DirectX SDK from Microsoft has several multi-monitor samples.

Multi-monitor and onboard video cards
This should work fine. If the onboard card is PCI, it will become the secondary card, if it is AGP it will most likely be the primary. Depending on your BIOS, it could also be possible that the onboard video gets disabled as soon as another VGA card is in the system.

Resource conflicts
Ron sent this tip for resolving resource conflicts: 'I had trouble installing my ISA Adaptec SCSI card which only works with IRQ 11. The IRQ Holder for PCI Steering only works with PCI. To install the ISA card, I had to first remove my second video card, install the ISA card, then reinstall my video card so it can grab another IRQ.'

Manually assigning IRQs: on Windows 2000/XP and later, you'll need to have set the computer type to a non-ACPI type, for example Standard PC, otherwise you won't be able to assign IRQs manually. For Windows 98/Me, see Microsoft Support.

Problems with interference
When adding a monitor, you may get interference, which will most likely show as a horizontal line wandering up or down the display, or as some sort of moving wave pattern.

To resolve this, try different refresh rates. If that doesn't help, you'll have to move the monitors further apart or put a shielding material between them. The ideal material is a thin nickle alloy sheet called mu-metal, available from LessEMF.com.

User-provided explanations of this problem:

>>> The interference between monitors occurs if the monitors aren't well shielded. Basically, monitors generate electrons which are focused and aimed at the screen to generate pixels; anybody this far knows this. The way you focus electrons is with electromagnets; if the monitors are poorly shielded and located too close to one another, the magnetic focusing of one can influence the focusing of the other (and vice versa). I didn't run across this on my multi-monitor system, but had a devil of a time when I was in college and working part time in the school's IT department. We'd line up a dozen or so machines right next to each other so we could laplink basic installations of everything from one to the other and had to deal with this kind of thing. My Samsung SyncMaster700's are literally touching each other with no trouble.
Moving the monitors apart helps solve the problem, as does changing their refresh rates (so that hopefully they aren't both focusing electrons at the same time). Putting something between them to block the magnetic field (a sheet of metal? a lead piece?) might help too. <<<

>>> There are magnets on the neck of any CRT (tv, monitor etc) and these are used for focusing during the set up. Some are glued to the neck, some are on bits of metal than can be bent for adjustment. However these would not cause interference between monitors as they are permanent magnets. The problem arises from the magnetic deflection coils that scan the beam from side to side and up and down the face of the tube. The large high frequency currents in these coils radiate a strong magnetic field that can affect nearby tubes as well as its own tube.
Magnetic shielding is the most difficult as there is no magnetic insulator (as there is for electric fields). The closest thing is a metal called mu-metal. This is used to shield photomultiplier tubes used in physics experiments. <<<

More information: Multimon forum, Microsoft Support.

Flashing the video card BIOS
If you have multiple cards of the same model installed, the BIOS flash program will just update the first card it finds. To be able to update the other cards, you'll have to remove every other card except the one you want to update.