Using your laptop as a second screen

Advertisers, Wall Street traders, and anyone who's ever fought for a share of the Windows desktop knows that the most important real estate on the planet is the screen you're looking at right now. And like all real estate, while some is good, more is better. We can't all have the quad-screen-from-hell, but a lot of us do have laptops or TabletPCs sitting next to our main display, and this post is about putting those extra LCD screens to better use.

You probably encountered what happens next as soon as you stopped thinking about how neat it was to have two screens on your desk, and started getting into a good work groove. It happens to everyone. You're in the zone, operating in flow, the computer as a seamless extension of your mind, until... you reach for information on the other screen, and nothing happens. Stopped cold, you look down and realize that you're using the wrong keyboard and mouse to get that information. Your concentration's broken, and you find yourself wishing that you could seamlessly move your mouse pointer from this screen to that screen, just like a real multi-headed monitor setup.

Thankfully, Scoble's blog has given pointers to no fewer than four tools that do just that: ShareKMC, Synergy, MaxiVista, and an internal Microsoft tool that I'll call "MSTool"*. What follows is a personal review of these tools - for a different perspective, see Loren's comparisons of ShareKMC vs Synergy, and ShareKMC vs MaxiVista.

  • ShareKMC: Probably the best known of the tools - use one keyboard and mouse to control two computers, hitting a key to flip focus between screens. ShareKMC emphasizes cut-and-paste functionality, and the latest release is significantly faster than earlier versions.
  • MSTool: My first love. Same basic approach as ShareKMC, but feels easier to work with because (1) it's even faster, and (2) you just move the mouse cursor off screen to change focus. Unfortunately like any good research tool it's got some rough edges: cut-and-paste only works in one direction, there's no support for extended keyboard and mouse functionality, and once or twice a day it would just wedge solid on me.
  • Synergy: Downloaded but not yet installed at the office - hey, it's Sunday! From the README and Loren's post it seems similar to the previous two, with the additional bonuses of cross-platform use and support for more than two screens, but some rough edges (e.g. limited cut-and-paste functionality).
  • MaxiVista: The latest contender takes a fundamentally different approach - rather than letting the two computers run independently, it uses a fake VGA driver so that your laptop becomes in effect just an extra screen for your host PC. The multi-monitor support in Windows XP promptly kicks in, you can drag-and-drop windows between the two screens, and some apps get smarter (e.g. Powerpoint 2003 drives both displays, showing edit mode on the first screen and slideshow mode on the second). Despite having to ship display bits over the wire, it's respectably fast.


Feature  ShareKMC  Synergy  MSTool  MaxiVista 
Switch focus using... Keyboard Mouse Mouse Mouse
Full cut-and-paste? Yes Partial One-way Yes
Perceivable lag? Slight ? None Slight
Rough edges? No ? Yes No
Laptop resources available?  Yes Yes Yes No

Right now I'm very happy with MaxiVista. If for some reason I lost my wired connection I'd go back to ShareKMC, and if I got a second TabletPC I'd check out Synergy. As for MSTool, the flakiness and the loss of my mouse's back-button outweighs the extra smoothness, so don't give up on ShareKMC yet Loren!

*This is not its real name, but after the Sideshow affair I'm taking no chances - Sideshow was a widely-used internal tool that was yanked after someone leaked the code. I'll return to it in a future post on "peripheral awareness"

Update: See also Scott Hanselman's review of MaxiVista from last year, and Gizmodo's review after my original post. Oh, and after the demo ran out I bought the full version.

Update^2: MaxiVista v2.0 lets you flip between "laptop as second monitor" and "laptop as second computer". Oh, and performance has gone from "respectably fast" to "can't tell it's not a real screen". Highly recommended.

Comments (15)
  1. Sinah says:


    thanks for the nice review. I have not heard about MaxiVista yet and it sound too cool to be true. But I tried and it works like a champ. I use a 100MBit LAN and it is unbelievable fast. Even video plays in full screen. Just reduce colors to 16 bit resolution as they suggest for increased performance.

    Just FYI, the makers of Maxivista have their own thoughts about other utilities as I found here:



  2. Agreed, MaxiVista sounds too cool to be true – so that myths page is trying to ground it in reality and convince people to just TRY it once! ("Here, kid, the first hit is free" :-)) I wish them the best of luck, and they’ll definitely be getting my $50 as soon as the demo runs out…

  3. Kneeding says:

    Jonathan Hardwick has a great blog article about an XP possibility: Using your laptop as a second screen. Jonathan reviews…

  4. Grid says:

    Damn cool software. ‘Nuff said. Grid

  5. Suzanne says:

    Can’t wait for the Maxivista extension. It looks too cool:


  6. MaxiVista is a software application that lets you use another PC – your laptop, for example – as an extra…

  7. Mark Millins says:

    Fantastic article. I went for synergy since I need to operate across 2 platforms (XP and Linux)and it works brilliantly. And whats more its free as it is supplied under the GPL even better!!

  8. Lynn Keen says:

    I have a HUGE problem.  My monitor blew up.  My laptop works and I’d like to use the monitor from the laptop as my main monitor between the desktop and laptop.  I wanted to install the MaxiVista, but don’t have a monitor to access the desktop to install.  Anyone have any helpful hints?

    PLEASE?  I am a web developer and loss of monitor means loss of development time and loss of business.  :+)



  9. David says:


    Well if you have configured your desktop to be able to be controlled remotely you could of course do that.

    Either with the built in "Remote Desktop Connection" or with Remote Administrator or some toher remote proggie.

    The trick is to install those kinda programs without having a screen. That you can’t do.

    Isnt it possible for you to borrow one?

  10. Bob says:


    Found this post while trying to figure if the screen (alone) from a broken laptop that will NOT power up, could be used in any fashion to "double" screen the laptop that I have that DOES work?

    Anyone with idea please write.  I have dismantled the laptop to get the 30Gig HD out of it, to salvage data, but hate to discard an otherwise good flatscreen.  Any other uses known?


  11. Sheila says:

    Would it matter if the primary laptop is a Vista and the secondary laptop (2nd monitor) is an XP?  Both computers are from the same manufacturer and their tech support said that with different operating systems, the monitors would be incompatible.  Any thoughts on this?


  12. lova raju says:


    I want to connect my laptop screen as a monitor i have no monitor hance i need to connect my desktop to laptop screen.  Is it possibel or not. if it is possible please give me suggestions.

    Thanking you,

    Yours obedently.

  13. Nuno Teles says:

    Guys, you need to look at Synergy. It’s not very straight forward to configure, but once you manage it, it works like a charm. On top of that it’s free and opensource!

    You switch between computers with your mouse and it just works naturally.

    Give it a try.

  14. Johndoe says:

    I tried maxivista demo and it felt nice except for a bit of lag on the second screen on the mouse movements. Felt more like low framerate. Could be cause it was a demo version, or maybe cause it was running in 32bit color? Anyhow, 40 dollars seems high for a program where there’s a free alternative. Is synergy really that good?

  15. lily says:

    I wish they could come up with usb drive software for this.  So there is no computer installation as I cannot install any 3rd party software to my work computer due to corporate policy.  I am looking into both software and hardware option but no luck.  

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