Up until two months ago, multi-head meant very little to me. I don't know why because my line of work is perfect for this technology. I can't tell you how many times having to minimize or maximize a window in a development environment used to drive me nuts. Multi-head is one of those features that once discovered, you probably won't stop using it. One thing that kept circulating in my head during the initial Parhelia reviews was how you configured these things? How do you hook them up?
You would think that configuring the Parhelia for so many display modes would be difficult, which isn't the case at all. Let's look at some of the options you have, as well as some of the potential limitations.
Dual-head really has no limitation, per-se. If you only deal with two displays, then you're looking at the following configurations:
2 digital displays (LCD), each connected to DVI outputs #1 and #2
1 digital display (LCD) connected to DVI output #1 and the second display (LCD/CRT) connected to the DVI-to-Analog converter
The Parhelia actually provides two distinct DVI connectors, which is a useful feature when dealing with LCD panels. Despite what you may have read, LCD's look better when paired with DVI as opposed to analog connectors. Here's how PowerDesk addresses this configuration.
PowerDesk Multi-Display Panel
In selecting the 2 displays option, you end up with 4 choices, one of which isn't visible in the screenshot:
1 display + 1 feature display
2 displays in independent mode
2 displays in stretched mode
2 displays in clone mode
Independent mode basically means that each display is treated as a completely separate display altogether. Stretched mode literally expands the desktop from the main display all the way to the second display, while clone mode will duplicate the contents of the primary display onto the secondary display.
Triple-head, unfortunately, has a couple of limitations that should be discussed. First of all, you cannot run any single display higher than 1280x1024. For those considering pairing a Parhelia with LCD's, this isn't a huge issue since many consumer LCD's support a 1280x1024 native resolution. If your LCD supports a native resolution of 1600x1200, you'll have no choice but to use a non-native resolution. If you're unfamiliar with LCD's, most panels tend to look worse when run in non-native resolutions although it tends to vary. In my case, the Dell FP2000 doesn't look too bad when run at this resolution, but I've had other panels that looked noticeably worse under such circumstances.
CRT's are different, in the sense that there's no real native resolution so you could potentially lose out on some screen real estate. In other words, you might be somebody who would run their CRT at 1600x1200 under normal circumstances. However, this limitation would force you to use 1280x1024.
Triple-head mode also limits your DVI capability as well. Despite the fact that the Parhelia has two distinct DVI connectors, the second DVI connector must be connected to a splitter cable, which has two analog connectors on the end. In other words, the center/primary display may be connected to DVI output #1, but the left/right displays must be connected to the analog connection on your display. For CRT's, this isn't an issue. LCD's, on the other hand, are a different animal altogether. As an example, my Dell FP2000 looks bad when connected to an analog output, but the Dell 1900FP looks much better. However, no matter how you slice it, hooking an LCD to the analog output will look inferior to that of digital.
In addition, triple-head only supports stretched mode. All of these limitations should be considered, but I'm here to tell you that the benefits outweigh these items.
Another feather in Matrox's cap is that the Parhelia allows you to set different resolutions and refresh rates for your displays while under dual-head mode. When you're in triple-head mode, they must be the same for all displays.
Unless I'm mistaken, the GeForce4 doesn't allow you to do this. As a test, I installed my GeForce4 and never realized that this limitation existed. In any event, this is almost a requirement if you happen to be using displays that have different resolution limitations. Again, consider my current setup. I have a primary LCD that can handle 1600x1200, while the other 2 LCD's only go up to 1280x1024. Unsing the GeForce4 and nView, I was forced to go down to 1280x1024 on both displays. On the Parhelia, I had to do a similar thing, but only under triple-head mode, not dual-head.
As an example, I've provided a digital image taken from my home office.
Hopefully, this image was good enough to give you a feel for just how awesome having that level of screen real estate can be. For the software developers who might be wondering:
Left display - JBuilder 7, Java IDE
Center display - Visual Studio 6 C++ IDE
Right Display - MSDN
I was working on a project that required debugging a chunk of C++ code in Visual Studio that was being called from a Java application. Ordinarily you would be forced to minimize/resize/maximize a series of windows in order to access each application, but triple-head allows you to see the "whole picture." I can't tell you just how productive this environment is for development work and I would venture to guess that it would be equally ideal for graphics artists, technical writers, and the like.