Multi-Display Graphics Suites Compared 249
Bender writes "There's an interesting comparison at TR between the major graphics players' multi-desktop software/hardware suites, like NVIDIA's nView and Matrox DualHead. These suites provide monitor positioning, application-level window memory, multiple virtual desktops, and the like. This is necessarily a Windows-centric comparison, but it's interesting to consider how Linux, X, and various desktop managers would match up with these solutions in terms of features and abilities."
I use Dualhead in X (Score:4, Informative)
I dread having to use computers with just one screen now; I don't think I could ever go back. I'm thinking about hooking up a third monitor, actually. Need a reinforced desk and a small nuclear generator to power all this crap though.
Re:ATI Radeon 9000 in new Mac G4s (Score:5, Informative)
No.
What about Quartz acceleration, is it on both displays simultaneously, or just one at the time?
Both displays at once, given sufficient (64MB) VRAM.
Do the popups show up in the middle of one screen or split between the displays like on the Matrox/PC.
Dialog boxes and other messages are typically centered on the display containing the menu bar.
Apple did multiple screens first, and it shows up in the more elegant handling of interface elements across displays and the general flexibility of those multi-monitor options compared to the "divided" dialog boxes and hardware constraints of Windows.
Re:Change X resolution and Virtual Res on the fly? (Score:3, Informative)
This is part of the RandR [xfree86.org] extension, wait for XFree86 4.3. This was mentioned [slashdot.org] some time ago.
Re:Multi-monitor in Linux... (Score:1, Informative)
I suppose it's only natural that, with PCs growing ever more powerful and capable of performing multiple tasks at once, we'd put them to use doing just that. And the more tasks you have going on at once, the more constrained you'll be by the limited desktop area provided by even a screen capable of resolutions as high as 1600x1200. The next logical step is adding a second monitor, or perhaps a third, but what's going to drive those extra monitors? You could go with an AGP card plus an additional PCI card to drive that auxiliary display, but PCI graphics cards aren't easy to find, especially if you want something with good video signal quality. Why not just run two or more displays with a single graphics card?
If you're ready to take the multimonitor plunge, you have a few choices. There's ATI's HydraVision, Matrox's Dual and TripleHead, and NVIDIA's nView. Each multimonitor system juggles hardware compatibility with software features in an attempt to make the most of an multimonitor desktop. Which one is right for you? Let's find out.
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Multimonitor setups explored
For some time, Windows has been able to recognize multiple graphics cards in a single system. Years ago, it was quite convenient simply to add a PCI video card in addition to a primary AGP card to support a secondary display. In time, graphics companies caught on to the multimonitor idea and started supporting multiple monitors on a single graphics card. It's a good thing they did, since good PCI graphics cards are so hard to find these days--just ask anyone with one of Shuttle's non-AGP-equipped cubes.
Windows XP allows multiple-output graphics cards to drive multiple displays to create a single, unified Windows desktop in an expanded workspace. WinXP will also allow a secondary display to mirror the contents of a primary screen. Really, it's up to you how you make the most of a couple of monitors.
That's all there is to multimonitor graphics, at least on the surface. However, there are at least a few compatibility problem areas to keep an eye on, and a lot of feature differentiation between offerings from various companies. I've highlighted some particular areas of concern below.
Some of the above terms and categories may not be clear for those unfamiliar with multimonitor setups, so I'll go over them one by one. Incidentally, I'll try to keep track of functionality in both Win2K and WinXP through the course of this article, but the various multi-display implemantions vary in quirky ways between Win2K and XP. My primary focus will be Windows XP, since it's the newer OS.
Independent monitor settings - When running an extended desktop on a multimonitor graphics card across multiple displays, Windows XP sees each monitor individually. This means that you can manipulate each display's resolution, refresh rate, and color depth independent of other displays in the multimonitor setup.
Here, compatibility issues arise with Matrox's TripleHead three-screen configuration, which we'll cover more a little later. Additional incompatibilities also arise with Windows 2000, where only Matrox's DualHead is capable of adjusting the resolution, refresh rate, and color depth of multiple monitors independently.
XP desktop support - There are two primary ways to display a Windows XP desktop on multiple monitors, you can stretch it or extend it. A stretched desktop treats a multimonitor configuration as a single, widescreen display and requires that each monitor's settings (refresh rate, screen resolution, and color depth) be the same. Though you are limited to equal monitor settings, a stretched desktop lets the Windows taskbar extend across all the screens in a multimonitor setup.
If you don't need your taskbar stretching across multiple monitors, or if you want to run independent monitor settings, you'll need to run an extended Windows desktop. Here, only the actual desktop area (not including the taskbar) extends to auxiliary monitors, and Windows sees the configuration as a series of individual displays. With an extended desktop, you can adjust the orientation of auxiliary displays to be above or below your primary display rather than locked down beside it in a widescreen stretched desktop.
3D acceleration spanning - Just because you can stretch or extend your desktop area over multiple monitors doesn't mean that a multimonitor graphics card's 3D acceleration will necessarily have the same flexibility. This category is particularly important for 3D professionals looking to extend their effective workspace, but it's also important to gamers looking for a widescreen gaming across multiple monitors.
Virtual desktop limit - All the multimonitor graphics cards we're looking at today support multiple virtual desktops that further extend Windows' desktop real estate. The implementations are actually quite similar, with the primary difference being exactly how many virtual desktops are supported. Despite theoretical limits, though, the number of virtual desktops that a machine can handle, and that your brain can realistically manage, is likely to be well within the capacity of even HydraVision's nine-desktop limit.
Intelligent monitor detection - Having a multimonitor setup is great, but what happens when your buddy's over for some LAN gaming action and wants to borrow one of those monitors? If you unplug a monitor and reboot, HydraVision and nView automatically turn off any multimonitor settings and reduce your desktop to a single display. Dual and TripleHead, however, retain an extended desktop even after a reboot with only a single screen. This might not seem like a big deal, but if you have applications set to open on the missing display, you're going to have a hard time getting at them until you plug that auxiliary monitor back in.
Application position memory and preferences - While all the multimonitor products we're looking at today will remember an application's window size, monitor, and desktop position, Matrox and NVIDIA offer further controls that can be bound to individual applications. Matrox's settings pertain only to 3D applications and their preferences for things like antialiasing, but nView is capable of manipulating various multimonitor window properties on an application-by-application basis.
I've only touched on differences between these implementations here, and I've omitted a number of areas where there's no meaningful differences between the different multimonitor products. Let's take a closer look at each one for a little more detail.
The Radeon 9700 Pro made a huge splash when it was released this summer, but there's more to ATI than just 3D graphics performance. HydraVision is ATI's flavor of multimonitor graphics. ATI has been developing HydraVision for years now. While ATI's 3D graphics drivers have been problematic in the past, their software, particularly MultiMedia Center, has been excellent.
To test HydraVision, we're using ATI's Radeon 9000 Pro. It's not as flashy or expensive as the other graphics cards we're using to evaluate multimonitor support, but it'll do. For a more complete look at the Radeon 9000 Pro, see our comprehensive review.
Like the 9700 Pro, the Radeon 9000 Pro has two 400MHz RAMDACs integrated right on the chip to power analog displays. The Radeon 9000 Pro chip also incorporates the TMDS transmitter necessary for a DVI output and a video encoding unit. Integrating all the necessary display logic on-chip is a neat way to do things, and it makes for a pretty sparse board layout.
Since LCD monitors are becoming more popular, I'd like to see dual DVI outputs on more graphics cards. Of course, the Radeon 9000 Pro isn't exactly a high-end part, so I'm not sure I can fault ATI for not going with a dual DVI setup here. However, I have yet to see any of ATI's Radeon 9700 Pro cards equipped with dual DVI outputs, and I want dual DVI outputs if I'm going to be dropping that much money on a graphics card.
As we saw in our comparison chart, although independent refresh rates, resolutions, and color depths are supported by HydraVision in Windows XP, they don't work in Windows 2000. These limitations also extend back to Windows NT 4.0, but curiously, not to Windows 9x. For businesses on the NT platform that haven't migrated to Windows XP, this limitation may be especially crippling. (Incidentally, ATI's official stance on independent resolutions and refresh rates in Windows 2000 is that it doesn't work, but I've heard reports of people getting it working with the 2.2 CATALYST drivers on the Radeon 9700 Pro.)
Also worth noting:t HydraVision doesn't seem to support stretched desktops in Windows XP. You can still extend your desktop to a second monitor, but your Windows taskbar won't follow.
From within ATI's CATALYST driver, you can only get at some simple display calibration tools. Full HydraVision functionality requires a separate download from ATI's web site, which is a little annoying. ATI seems to prefer splitting up its driver components into separate downloads, and you've got to reboot after installing each component. Ugh.
What's particularly interesting about ATI's multimonitor support, at least with the Radeon 9000 Pro, is that it runs in clone mode while booting. It does the same in Windows until you install the HydraVision software. The fact the secondary display is activated during the boot sequence may be particularly useful in special cases where you want screens displaying the same thing in multiple locations.
Once you've downloaded and installed the latest HydraVision release, ATI gives you a few tools to play around with--"few" being the operative word here. There's support for multiple desktops (up to nine), a "move to monitor" feature, an Internet Explorer extension that lets you open a hyperlink to a specific monitor, and some transparency and fading effects. All in all, nothing particularly earth-shattering, though the ability to scroll through multiple desktops with the mouse wheel is a nice touch. HydraVision also supports application position memory and the ability to intelligently position dialog boxes, but these features are shared by Dual/TripleHead and nView so they're not unique to HydraVision.
Re:ATI Radeon 9000 in new Mac G4s (Score:2, Informative)
This is just completely untrue. Apple did do multi-display first, but Windows is every bit as good at handling multiple displays. If you put two ore more video cards in a box (which is what I've done since Win'98 originally came out), Windows handles multimon beautifully. Dialog boxes centered on active display, windows maximized to single display, etc.
The problem is that most dual-head video card makers, up until recently, have provided drivers that tell Windows "Hey, this is one big, wide display!", and Windows has no way of knowing that it's centering a dialog box across 2 monitors. Matrox has fixed this (finally) in their drivers, and ATI has as well with the drivers for the 9000 and 9700 -- the 8500 and earlier still haven't been fixed. (I don't know about nVidia, tho').
Get a real multimon solution for Windows and you won't be disappointed. I'm running a 3 19" displays at work -- 4800x1200 resolution is great.
--Jeremy
Re:I use Dualhead in X (Score:3, Informative)
Triple headed Linux beast of doom (Score:5, Informative)
This caused me to look at using multiple cards instead of multiple headed cards.
I have one 21" and two 17" monitors, and I wanted the primary display (21", middle, AGP) to be able to be upgraded seperately from the secondaries (PCI, one on either side of the primary), as I have no interest in spanning 3D games across screens. Granted, I could have done three with the Matrox card, but then I'd always have to upgrade to another 3-monitor card. The solution I went with was to have one nVidia AGP card for the primary (currently a TNT2 Ultra, to be upgraded later) and two GForce 2 PCI cards for the secondaries. The GF2s are plenty fast for 2D, and fast enough to run small 3D accelerated toys/apps/screensavers too. The only downsides are the use of more expansion slots than using a dual-headed card and that 3D acceleration won't span. The upsides are that each one is running full speed, they're completely independant so multiple resolutions/frequencies is less of a problem, and the primary display can be upgraded seperately from the secondaries. I believe I could also run seperate X servers on each card if that ever became useful.
So if you want spanning 3D acceleration or are low on expansion slots, go with a multihead card. Otherwise, think about doing it this way.
OK, so there isn't a lot of real content in this post, but I thought I'd share a setup success story. When doing multi-card multi-head systems I'd *highly* recommend sticking with the same chip line/maker, and I'd just as highly recommend it be nVidia. Getting these three cards working together couldn't have been simpler...
Re:Going back to one display might suck... (Score:3, Informative)
Re:Multi-monitor in Linux... (Score:2, Informative)
(*still shares mouse and keyboard, ie which ever screen you got the (core) mouse on has focus)
an advantage to windows is that you dont loose HW acceleration when ur spreading desktop. While w/ xinerama you do. but not with the multi WM setup. (which is what I use)
And setting up either aint that difficult, I remember when I was still using mdk (2 years ago) that the CD installer could even do it (I think it was 8.0)
Re:Colorgraphic's Predator (Score:2, Informative)
But You haven't tried a Matrox, have you...
You wouldn't go back. The powercolor had OK NT drivers, but they were pretty unfriendly and limited cards compared to the Matrox cards.
And no, I don't work for Matrox.
Help for nView people (Score:2, Informative)
WRONG!
There is a simple registry tweak that will enable a checkbox to "Treat multiple outputs on an nView-capable board as seperate display devices". All that has to be done is disable nView in its control panel and apply this to the registry:
[HKEY_LOCAL_MACHINE\SOFTWARE\NVIDIA Corporation\Global\NVTweak]
"NvCplExposeWin2kDualView"=dword:00000001
Reset the system and find the checkbox, I have it under advanced> Desktop utilites.
RE: Triple headed Linux beast of doom (Score:2, Informative)
If you want a 3 head machine for cheap, I'd reccommend getting Matrox Millenium II PCI cards ($20 on ebay). You can stick up to 4 of them in one machine. I have an AGP Geforce2 as my center display, and use that for games. The Mellenium IIs are plenty enough for stuff like xterms and web browser windows, and the geforce card runs games well. It was all surprisingly easy to get working.
I dual boot linux and XP, both OSses support the display set up fine. XP acts kind of bizarre when you start a game on the center display and it changes resolutions though.
If anyone wants my XF86Config file I'd be happy to post it.
To confirm your belief about running separate X servers on each display: yes that is possible, I've done it before. Its a good way to get everything debugged as you're getting it all configured. The problem with separate X servers is that they would be conflicting for your input devices. A better way would be to use 1 X server, but configure it for multiple displays. Each display will be separate and will have its own minor display number (:0.0,
Why bother with these when there's UltraMon? (Score:2, Informative)
I run dual 17" monitors (GF4 MX and a GF2 MX) on Windows 2000 Professional and I don't even bother with NVidia's NView app. Haven't found a single use for it other than it being unreasonably slow for features I don't need. For everything Windows 2000 doesn't do out of the box, I just use UltraMon [realtimesoft.com].
UltraMon still leaves a bit of a memory footprint but it's not nearly as bad or as slow as NView. It's this unobtrusive (and persistent) little system tray icon that gives me all kinds of settings that NView seems to offer as well, except faster. Some of the features I appreciate in particular are:
Shortcut keys to swap programs between monitors (proportionally or to fit - INCREDIBLY useful if you run different resolutions)
Shell extensions for switching monitors or maximizing.
A simple double-click on the systray icon (or a definable keyboard shortcut) to turn off the secondary monitor on demand, such as if you want to run an OpenGL game without the second monitor looking all weird.
Individual desktop wallpaper settings.
The program itself creates shortcuts that set a program to start on a certain monitor.
Saving window sizes and positions.
You can enable two separate taskbars if you want, and either have each taskbar show all the tasks or have each separate taskbar show the tasks running on that specific monitor.
That's the bulk of its features. Great little program. Unfortunately, yes, it is $40 to register, and there are discounts for multiple licenses, but for me personally it was well worth the cost for the extreme ease of use it provides me with my monitors.
I have tried NView, but it kind of seems like it's trying too hard to be useful, where UltraMon just works, and works great. I'd definitely recommend it for anyone with dual monitors.
Re:Personal review: They all suck. (Score:3, Informative)
It was an important discussion around here before we moved some of our drawing code into OpenGL. Once we solved that little problem though, and wrote a class to get it all initialized properly, all was good, and writing dual-monitor friendly OpenGL apps is easy.
Don't ask "Well then, explain how?" because I'm not obliged or willing to say. The code is not GPL. But it can be done.
As for your comment about debugging software using two monitors, I wholeheartedly agree, and couldn't live without it anymore.