Thursday, December 04, 2008

Adding a 3rd Monitor to a Laptop

Back in September, I set up about researching how I might be able to add a 3rd monitor to my laptop PC at work, a Lenovo (IBM) ThinkPad T60.

The built-in video card on the laptop PC, an ATI Mobility Radeon X1300, supports only dual monitors.  The card can run the built-in laptop LCD display plus one external monitor, or two external monitors (via the additional DVI port on the machine's docking station), but not two external monitors and the built-in LCD at the same time.

Since simply opening up the case and popping an additional video card into a free PCI-e or PCI slot isn't an option with this laptop machine like it would be with a desktop machine, I considered several alternative solutions:

Docking Station PCI Card

I first considered purchasing a new docking station, the Thinkpad Advanced Dock, which supports adding a standard PCI-e card directly to the dock; then plugging a PCI-e video card into the dock, and running the 3rd monitor off of that. 

However, this solution was cost-prohibitive (around US $380 for the dock -- not including the cost of a PCI-e video card).  I also ran across multiple reports from Thinkpad owners trying and failing to get this solution working on the official Lenovo forums (particularly in this thread).

PCMCIA Video Card

Next, I looked into the possibility of getting a PCMCIA video card for my laptop's free PCMCIA slot, such as the VillageTronic VTBook

However, I was somewhat concerned that the card might "stick out" of the side of my laptop, making the laptop a hassle to carry around with the card installed.  I was also concerned about potential difficulties with docking/undocking the machine (which I do a few times a week) while using the card.  Finally, the VTBook solution was also somewhat cost-prohibitive (around US $250).

My solution: USB Video Card

The solution that I finally settled on was to purchase a USB 2.0 video card.  This is a self-enclosed video card with a USB connection on one end to connect to the PC, and a DVI port on the other for connecting a monitor.  The specific model I picked up was an IOGEAR model GUC2020DW6 external video card.  The price was right (particularly compared to the other available laptop multiple-monitor solutions I considered): the IOGEAR card was on sale for about US $80 when I purchased it back in early October 2008 (and it's even lower now, down to US $68 on Amazon, as I write this post). 

I've had the card for just about two months now, and it's been working great -- better than I expected!  I had been concerned that there might be noticeable display "lag" on the monitor connected by the USB video card, but in practice, there's no noticeable difference when working on the USB-connected monitor or working with one of the others.  The only time that I notice the difference is when dragging a window around on the USB-connected monitor; there is just a bit of "lag" as the window moves around the screen.

Here's the card, connected, behind my PC, along with a penny to help show the size of the device (apologies for the low quality cellphone-cam photo):


And here's the 3-monitor setup at my desk at work, using the external USB video card to drive one of the external monitors:


USB video cards do have known limitations with displaying very rapidly-updating content (e.g. movies, 3D games) due to the limited throughput of USB 2.0, so I wouldn't purchase one of these cards to use on a gaming machine.  However, I knew that I'd only be using this monitor for business use: Writing code, viewing documents, doing email, surfing the web; that type of thing.  Also, in the event that I do want to view some rapidly-changing content that the adapter can't handle well, I can always just put that content on one of my other monitors.


I got some great help in my research on this issue by posing the question of ways to add a 3rd monitor to a laptop over on StackOverflow, a fairly new community-run site for asking and answering programming and programming-related questions.


  1. Thanks for sharing that. It is good to know that USB is an alternative for monitor extension.. :)

  2. Great post...thanks Dad!

  3. Nowadays there are monitor that comes with a USB connection. Does this mean you don't need to use the external converter. Wonder how many USB monitor can be connected to a single laptop, 3 or 4?

  4. Any trouble un-docking with your setup? I've got the same arrangement (but T61 & advanced mini-dock) and even when disabling the display & the device via device manager I still get a message when undocking that it can't undock because the device connected to the docking station is still in use.

  5. @Anonymous (10/26): I'm not sure: Unfortunately, the USB ports on my Lenovo Advanced Mini-Dock all died 13 months after I got it. (Yes, as you might expect, the docking station had a 12-month warranty!) So I just plug the adapter directly into the laptop's own USB port. I just unplug the USB cable (without doing a "safely remove hardware" in Windows) prior to undocking, and everything works fine.

    As a suggestion, you might try stopping the
    "DisplayLink Service" in Control Panel | Administrative Tools | Services, and see if you can undock successfully after the service is disabled. (After you re-dock, you'd need to restart the service to get the USB video card working again.)

  6. @Anonymous (10/26): A new driver has been released for the IOGEAR GUC2020DW6 that corrects the undocking issue! The Windows service installed by the driver software is now called "DisplayLinkManager" (not "DisplayLink Service"), and on my new Lenovo ThinkPad T500, it automatically handles turning off the 3rd monitor when undocking, and turning it back on when re-docking. It works great.

  7. Thanks for the great information. I have often wondered how you get more than one screen connected. Very Cool!

  8. Hey, nice site. I will definitely be visiting here more regularly. I wish that I could add the post and bring a bit more to the table... Quite informative..

  9. Hi Jon - was so excited to see this post, as I have been trying to figure it out for a while, but am not a tech person. Nonetheless, my question is, does this solution work with a widescreen monitor? In your picture, I can't tell if the IO video card is linked to the regular Dell monitor, or what seems to be a widescreen Samsung. I have two widescreen monitors, so am trying to find a solution where I can hook up both of them to my Lenovo ThinkPad. Any info you have would be tremendously appreciated!

  10. Anonymous (1/11/2012), I'm currently using my GUC2020DW6 (the same one I bought back in 2008, when I originally wrote the post above) to drive a Lenovo Thinkvision monitor running at 1440x900 resolution (which is a 16:10 widescreen resolution). So, yes, it works for me!


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