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USB Monitors? DisplayLink's Technology, Examined

USB Monitors? DisplayLink's Technology, Examined
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Would you like to add another monitor, but find yourself out of display outputs? DisplayLink's technology employs the USB bus to extend your screen. The current implementation isn't perfect; we're more excited about the USB 3.0 hardware it has planned.

According to a recent poll we posted to our Facebook page, 61% of you currently own a notebook. If you don't, there's a chance you simply have no need for mobility. Or perhaps you've replaced the heft of a mobile PC with a tablet or smartphone for tasks like answering email or online banking. Nevertheless, we expect the percentage of notebook owners to rise as performance increases and prices continue to drop. 

The appeal of notebooks is clear. Plopping down on the couch to browse the Web is far more relaxing than sitting at the same computer desk day after day. But that freedom comes at a price. Even when you move past the fact that mobile systems are necessarily slower at the same price point, you're generally still restricted to a single screen.

Solving that issue isn't easy. Some notebooks include a second display output you can use when there's another monitor available. And we've seen a handful of laptops with AMD-based GPUs that expose Eyefinity functionality, accommodating a third screen. But there aren't many of those around. So, how do you get the flexibility to connect three of four displays at a time? DisplayLink has a solution in its technology that enables graphics over the USB bus, connecting to monitors with USB inputs.

These devices are handy in a pinch, but how do they actually work? We take a deeper look at this technology so you know what to look out for before buying multiple monitors for your mobile workstation.

Test Setup

System
MacBook Pro 2010 13.3"
Lenovo ThinkPad T410
Processor
Intel Core 2 Duo, 2.4 GHz
Intel Core i5-540M (Arrandale), 2.53 GHz
Motherboard
-
-
Memory
Crucial DDR3-1066 8 GB (2 x 4 GB)Crucial DDR3-1333 8 GB (2 x 4 GB)
Hard Drive
Western Digital Scorpio Blue 1 TB
Seagate Momentus 5400.6 500 GB
Graphics
Nvidia GeForce 320M
Nvidia Quadro NVS 3100M
Power Supply
-
-
Network Card
-
AirPcap Nx USB Adapter
System Software and Drivers
Operating System
Mac OS X 10.6.7
Windows 7 Ultimate 64-bit SP1
DirectX
-
DirectX 11
DriversDisplayLink 1.6
DisplayLink 5.6


All performance testing is performed using a Plugable USB-to-VGA adapter.

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  • -1 Hide
    vdr369 , August 30, 2011 5:51 AM
    looking good, and pretty useful too, it is very useful for notebook users, does this product released in India.
  • -1 Hide
    soccerdocks , August 30, 2011 6:43 AM
    My notebook has 3 extra outputs. VGA, HDMI, and Display Port. That's plenty for me. I don't see too much of a use for this.
  • 7 Hide
    nevertell , August 30, 2011 7:22 AM
    When are we going to see DP connectors on most mainstream graphics cards and monitors ?
  • -4 Hide
    SteelCity1981 , August 30, 2011 8:44 AM
    So when USB 3.0 ports goes to 100w this will eliminate the need for a display link i'd imagine.
  • -2 Hide
    mister g , August 30, 2011 11:49 AM
    nevertellWhen are we going to see DP connectors on most mainstream graphics cards and monitors ?

    When Nvidia does so on all their graphics cards, and when manufacterer's finally get the big idea and choose between paying for Displayport or to the DVI Consortium. IGPs also need to switchover or else it won't work.
  • 2 Hide
    WyomingKnott , August 30, 2011 1:16 PM
    soccerdocksMy notebook has 3 extra outputs. VGA, HDMI, and Display Port. That's plenty for me. I don't see too much of a use for this.

    For you, no. Other people might find it useful, though. Especially with ultra-portables or other compact devices that tend to have only USB and headphone ports.
  • 2 Hide
    JohnnyLucky , August 30, 2011 3:24 PM
    I didn't know modern laptops, notebooks, and ultra notebooks might not come with with connections for an external display. I would have thought a connection for an external display would have been standard. Way back in 1993 I purchased a Sony laptop that had an extra video connection. I used it to connect a 21 inch flat screen CRT monitor.
  • 5 Hide
    jamie_1318 , August 30, 2011 3:53 PM
    I don't think I've ever seen a laptop without at least one external monitor plug. I don't see that being useful to me at least because I don't see needing three screens on a laptop in the immediate future. (I can already dual screen by using the Notebook's display).

    SteelCity1981So when USB 3.0 ports goes to 100w this will eliminate the need for a display link i'd imagine.


    laptops don't have 100w of power to output to a external GPU, they are probably not going to be on board with this technology. Besides which USB3 is nowhere near fast enough to feed data to a Graphics card in real time, without ever bothering to talk about latency or data-loss. It might be useful if they put very low end Graphics card and powered them off of the USB port, I don't see it becoming common enough to obsolete display port for some time.
  • -3 Hide
    soccerdocks , August 30, 2011 4:28 PM
    WyomingKnottFor you, no. Other people might find it useful, though. Especially with ultra-portables or other compact devices that tend to have only USB and headphone ports.

    My point wasn't that there was no use for this. Merely that there was a small market for this product.
  • 0 Hide
    ram1009 , August 30, 2011 5:16 PM
    I find myself disagreeing with the whole premise of this topic. Why would anyone want to use a portable while there was a more powerful desktop nearby? It just doesn't compute. IMHO, portables are only to be used for those things you can't do on a desktop.
  • 0 Hide
    SteelCity1981 , August 31, 2011 12:59 AM

    laptops don't have 100w of power to output to a external GPU, they are probably not going to be on board with this technology. Besides which USB3 is nowhere near fast enough to feed data to a Graphics card in real time, without ever bothering to talk about latency or data-loss. It might be useful if they put very low end Graphics card and powered them off of the USB port, I don't see it becoming common enough to obsolete display port for some time.



    They could use a cycle mode when the laptop is plugged in the usb 3.0 goes to 100w's when it's not it stays at 4.5w
  • 2 Hide
    Anonymous , August 31, 2011 4:56 AM
    I like that you show a HP monitor! haha
    Poor HP i will miss them. On the device market.
  • -2 Hide
    palladin9479 , August 31, 2011 5:54 AM
    This technology is actually being used right now to "far throw" a system's display to other rooms. We have several specialized systems that drive display's across a large command center and running RGB cables everywhere lead to a distorted image.
  • 0 Hide
    joshyboy82 , August 31, 2011 8:06 AM
    So this device could be potentially useful to even a desktop crowd, the group that has only one Nvidia card and would like to run three monitors for productivity. It'd be nice if a USB3 version would come out.
  • 0 Hide
    Anonymous , August 31, 2011 2:47 PM
    I got one of these around christmas time (2010) for my work pc. Unfortunately, the particular model of my work pc wasn't compatible with the DisplayLink product. Their support and assistance was terrific however. Eventually, I decided to bring my laptop to work and use that instead (it is much more powerful anyway). My laptop has one extra output, so I figured I would use the displayLink product for a third monitor. I have been using it ever since. It is excellent, I generally use the displayLink attached monitor for having my Outlook open and my database management studio if I need reference to data while I am programming. The resources used are never noticeable and it has worked reliably and effortlessly every day. A very excellent product in my opinion. My only suggestion is to research what you plan on using it with/for and ensure that it is compatible.
  • 1 Hide
    jamie_1318 , August 31, 2011 2:57 PM
    @ steel city, Laptop power adapters are rarely even 60w, so the 100w standard could never really be feasible without changing the circuitry. you could theoretically (and in practice) drain the battery life to provide 100w of power, but that's not even the main issue here. you could use an external adapter to power an external GPU, but USB 3 is no where near fast enough to power anything but a very low end Graphics card. Essentially USB 3 is as fast as a single pci-e 2.0 lane, plus added latency to deal with and signal deterioration.
  • 0 Hide
    DrgnRebrn , September 1, 2011 12:54 AM
    I have been working with a 3 monitor setup for over a year now, utilizing the VGA & DVI connections on my HP docking station in conjunction with a USB-to-DVI adapter. Two of my LCDs are 23" set at 1920x1080 and the third LCD is a 24" set at 1080x1920 (portrait). This has become my favorite monitor for viewing PDF & Word files as well as for browsing the internet on. This is the monitor I have connected through the USB2DVI adapter. The other 2 are landscape monitors and are primarily used for viewing spreadsheets, email (one on each monitor), and database programs. I cannot work any other way now! I have never experienced any issue whatsoever in using the USB2DVI adapter, although I did spring for the "Pro" version which supported resolutions beyond 1024x768. I am running an HP EliteBook 6930P with 4GB RAM. The 2x 23" LCDs are identical Acers, model S231HL, and the 24" LCD is an HP LA2405wg.
  • -2 Hide
    upgrade_1977 , September 1, 2011 4:02 AM
    Why not just get a Matrox TripleHead2Go instead of killing the cpu with compression decompression?
    Haven't seen a laptop in a long time that doesn't come with a vga, dvi, or hdmi out.

    http://www.matrox.com/graphics/en/products/gxm/th2go/
  • -1 Hide
    alidan , September 1, 2011 6:54 PM
    i read nothing but the first lines so far.

    you want a more accurate poll, make it on toms, because many of us despise facebook.
  • 0 Hide
    abdussamad , September 1, 2011 7:07 PM
    @palladin9479: You do know that you can run VGA over Cat5 cabling, don't you? I am sure you have lots of that in your data centre.
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