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DisplayLink – Multi-Display Setups with USB

Date: January 24, 2008
Author(s): Rob Williams

In a world where multi-tasking is a necessity, multi-display configurations are becoming ever more popular. DisplayLink is a new kind of technology that promises to take the hassle out of adding additional displays to your PC – even six is possible. Best of all, you don’t need a second GPU.


Ten years ago, Apple Computer released the iMac. What a day that was! I clearly remember being excited and disappointed all at the same time. I mean, it was a NEW Mac! But on the other hand, it was the ugliest Mac ever! But despite my disgust, one thing caught my attention fast – the introduction of the Universal Serial Bus. No more Serial and Parallel!

In those ten short years, USB has become the most popular connection-type for most users. Everything from our keyboards, mice, web cams, printers and even audio use the connection, in addition to thousands of various gadgets – including feet warmers and beverage coolers.

Thanks to the fact that USB offers great speed and is even able to power up our gadgets, the possibilities are pretty-much endless, and things should only get better once USB 3.0 hits next year. When USB 1.0 first launched, who imagined what it would become today? Who especially would have thought transmitting video would have been possible? Not many, I’m sure, but coincidentally, that’s the topic of todays article.

Video via USB – What’s the point?

Last summer, our friends at X-bit labs published a review of the first video-via-USB display, the Samsung 940UX. At the time, even I was skeptical… pointed fingers, and laughed. Having reviewed so many USB-base products in the past, I thought I had known the limitations of what could be accomplished, but I was wrong. As it turns out, the Samsung 940UX was only the first product of many to be released with such technology.

To understand why USB video is relevant, you first have to understand that this is not a technology set out to replace VGA or DVI if you have a system with a single monitor. If that’s the case, then it makes no sense to rely on USB, as VGA and DVI are faster and will allow full capabilities. USB on the other hand, is there for those people who either a) don’t have a spare video port on their computer, b) don’t want to install (or pay for) a second GPU and/or c) require two or more monitors.

With the help of DisplayLink-based products, up to six monitors can be hooked up to a system at any given time. Obviously, many people are not going to hook up six monitors, as that’s really hitting a specific crowd. However, as monitors become ever-more affordable, consumers are beginning to contemplate the purchase of a second monitor to aide with multi-tasking. Some people may also have old monitors in their closets that could be put to good use.

It’s a fact. If you have more than one monitor hooked up, multi-tasking is made far easier. Personally, I prefer to have a single large monitor (such as a 24″) than smaller identical monitors, but many will disagree. Our own Greg King for example, absolutely loves a three-display setup. He has gone as far as to admit he prefers a 3x 19″ setup more so than his Dell 24″. Though multiple displays could prove less ideal for gaming, the multitasking ability sky-rockets.

Finances on center screen, web browser on left screen, IM conversations on right screen… these types of scenarios are where multi-display setups excel. But once again, for a three display setup, at least two video cards need to be installed. Unless DisplayLink is brought into the picture.

Multi-tasking aside, notebook users are another crowd that could feel the benefit, especially those with older models. Most notebooks today will include a DVI or VGA port, but not usually both. Recent notebooks I’ve had, have actually included HDMI and VGA, excluding the very-popular DVI altogether. That’s no good when you have a monitor that’s DVI-only. Using DisplayLink, however, a notebook could use the monitor fine, completely ignoring the fact that the notebook doesn’t include the appropriate connection.

How DisplayLink Works

Once setup, DisplayLink will be detected on your computer as another graphics card, or “Virtual Graphics Card” as DisplayLink likes to call it. So like most setups, DisplayLink consists of both hardware and software, with the software being absolutely required. Because of this, alternative OS’ will be unable to utilize the technology, unless DisplayLink releases fresh drivers in the future.

In order to transmit video to another display, DisplayLink’s software will convert the pixel stream into a lossless transport protocol and then send it through the USB cable and then the DisplayLink chipset, and ultimately, the display itself. This all happens in real-time. During normal use, there should be no delay on any of the displays hooked up.

The above photo was one that I snapped while checking out LG’s booth at CES earlier this month. Their new L206WU display utilizes DisplayLink’s technology, just as the Samsung 940UX does, and they were happy to show off the capabilities during the show. The system in the middle of all this was a simple notebook computer, but with the help of their latest monitors, they had access to a total of six displays.

If you’ve hooked up more than one display before, using a video card or two, DisplayLink’s setup will not be an uncommon sight. Everything, for the most part, will work just as you’d imagine a multi-display setup to. You can move monitors around if you please and also mirror and rotate, the latter of which would be useful if you decided to use a wide-screen vertically.

Who else is using DisplayLink in their products? We will discuss that, along with installation, next.

Installation, Testing

Before I knew what DisplayLink was, it became apparent fairly quickly that USB-display technology was catching on just from conversing with our usual contacts at this months CES. IOGear, creators of some of the glossiest products on the planet, showed off their External VGA Video Card (#GUC2015V), using DisplayLink’s technologies. At current time though, IOGear only offers a VGA connection, overlooking DVI.

eVGA also had adapters on display during our meeting. Called the UV Plus+, it serves the same purpose as the rest, to transmit video via USB to multiple displays. Their product is by far the best-looking out there, though. That’s easy to notice since the rest of them are as bland as a white wall. Theirs are also stackable, and solid enough so they will not move around on your desk by accident.

One of the more readily available offerings in the US market is Toshiba’s dynadock USB docking station. Built for notebooks, it allows you to connect to a DVI or VGA display, depending on the model you purchase. That issue alone is one that could confuse consumers. From what I can see, there are no DisplayLink products available that offer both DVI and VGA, it’s either one or the other. To make matters worse, most companies only offer one or the other, such as IOGear’s product. Ideally, a DVI version would be the best choice, even if you can’t use it at the time, since DVI-to-VGA adapters are readily available, and may even be included in some of the products.

That’s not everything to look-out for though. At current time, DisplayLink markets two different chipsets for these devices, the DL-120 and DL-160, with the difference being the performance capabilities. The DL-120, for example, will not utilize resolutions above 1280×1024 (or 1400×1050 wide-screen), while the DL-160 bumps up the specs to 1600×1200 (or 1680×1050 wide-screen). Luckily, most people should not have to worry about this, since the manufacturers site should clearly state the maximum allowed resolution of their device.

DisplayLink Installation

During CES, I happened to stumble on DisplayLink’s booth, which is actually the reason I found out what their company did. Until that point, I didn’t clue into the fact that the USB-display products I saw up to that point utilized their technology. Before I left, they slipped me a media kit, which contained two DisplayLink DVI adapters, various cables and the required software. Note that this is not a commercially available version, as DisplayLink themselves do not sell the end-product. Rather, their partners do.

No matter which method you choose to go with multi-display setups, the most ideal method is having all of your displays utilize the same resolution, just for the fact that when you have a couple different displays using a wild variation of different resolutions, it can hinder multi-tasking a bit. That said, I don’t have three displays of the same resolution, and instead used my television and Windows machine’s display to test out the capabilities.

First and foremost, the installation really couldn’t have been any easier. As you can see in the above photo, DVI cables (not included) must be connected to the device and then plugged into the monitor. From there, a standard USB cable runs from the device to your machine. In the case where DisplayLink is built into the monitor itself, such as with the LG L206WU, you just need to run the USB cable from one display to the next.

Once the hardware was connected, I installed the software and had a quick reboot. After the software installation, I was skeptical that Windows was going to boot and light up the external displays, but sure enough, it did. That… was by far one of the most easiest installations I have ever dealt with – not a single issue along the way.

To control the monitors, there’s a small icon in the systray that looks similar to the one Windows uses for network shared-storage, which also happens to be there. Right-clicking this will allow you to tweak the connected displays, whether by changing the color quality, resolution or rotation. You can also mirror a display or change it’s alignment, similar to how you can in the Windows display settings.

On the next page, I’ll continue with thoughts on testing and also wrap up with my final thoughts.

Testing Cont., Final Thoughts

Below is a straight Prnt/Scrn of the entire setup once done. The center screen is my ASUS 20″ monitor capable of 1680×1050. On the right is my LG television, running at the screens maximum of 1280×768. On the left is a Gateway XHD3000 30″ wide-screen. Normally this display is capable of 2560×1600, but since DisplayLink’s best chipset only supports up to 1600×1200, that’s what’s displayed here.

Because DisplayLink devices will be detected like any other graphics card, the built-in Windows display settings can be used to make any adjustments you may need. If you have identical monitors, nothing should have to be changed here, but if you have varying resolutions like I do, then it’s wise to drag around the monitors to your preference. I found having all of the displays align at the top makes the most sense, but your choice could vary.

During use, the entire setup ran like a dream. There was no lag dragging one thing to another screen, video played well (720p) and overall, it was hard to tell this was all being done via USB.

I did have a cursor-lag problem with the largest display, the XHD3000 at 1600×1200, but I believe that to be a problem of the monitor itself, not the adapter. That monitor shows slight lag at lower resolutions even through a regular connection, and there are other issues that I plan to cover in that displays review in the coming weeks. I regret not having another display handy capable of 1600×1200, but there was no lag whatsoever on the television at 1280×768, so I believe it to be a stable setup overall.

DisplayLink does warn against full-screen gaming, however, as the graphics are too difficult to render using their current chipsets. According to the company, new chipsets are in the works that should be released later this year to allow gaming. Even then, Windows Vista will be required due to the OS having abilities to render the graphics on the systems graphic card instead of on the DisplayLink VPU.

For regular use however, you should never experience any slowdown, regardless of how much work you are doing at a time. The primary downside is gaming at this point, but as long as you keep that to the primary display, there should be no lingering issues. I should mention that lightweight 3D applications are usually fine, such as Google Earth.

Final Thoughts

Prior to CES earlier this month, I had no idea how USB-video worked or more importantly, how well it worked. Even after leaving, I had no desire to investigate further until I realized I had a media kit hanging around. After setting everything up, I transitioned from not caring to completely understanding what it was all about. Overall, DisplayLink offers an impressive technology, and one that I awarded our Best of CES 2008 award to.

We might still be in the early stages of DisplayLink’s products, but already the adapters feel like a matured product. I ran into no severe (or even moderate) complications during all my use. The prime hitch was the lag on the Gateway monitor, but I am still leaning towards pointing blame at the display rather than the adapter.

Besides regular desktop work, high-definition videos transmitted fine as well. I don’t have a Blu-ray or HD DVD player to test out 1080p content, but I tested downloaded 720p content and it ran fine. I believe as long as you are running non-full-screen applications, you shouldn’t feel the effects of lag with whatever you are doing, but I could be wrong where 1080p is concerned. I plan to test that out once able.

As of right now, there are not that many companies who produce DisplayLink products in the US, but the ones that do can be found here. Both eVGA and Kensington will soon be releasing very similar adapters to what I used during my own testing here, and you can expect them to retail for around $99.

It has hardly been two weeks since I first learned of DisplayLink, and already I am interested in seeing what else they have up their sleeve… namely, chipsets that support higher resolutions. Pricing might be high for some, at around $99 per adapter, but to overlook purchasing a second GPU and the ability to hook up to six monitors will wipe out concern over that. That said, I do hope that the technology catches on fast so that prices will go down, and as a result, become readily available for everyone.

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