ScreenRecycler: Re-Using Old Displays

I’ve always been a fan of running multiple monitors with my Mac, and firmly believe that extra screen estate can have a huge impact on increased productivity and reduced clutter. Extending your desktop is fairly straight forward with OS X, and providing you own a compatible display it’s easy to connect to a laptop or desktop machine.

However, there are a number of scenarios where adding a new monitor isn’t possible; extending to another machine screen (e.g. an old iMac or laptop), extending to a Windows computer, or running more than one additional monitor from a laptop. ScreenRecycler is a great little app which can extend your desktop over the network to any old computer and monitor, regardless of whether it’s running OS X or Windows. This review will outline the features of ScreenRecycler and explain how it works.

Essentially, ScreenRecycler allows you to extend your desktop to any other computer. Whether this is an old MacBook/iMac or a Windows laptop, you can have your additional screen space up and running in no time at all. It works through your network (preferably a wired network) to transmit data over VNC whilst tricking OS X into treating the second screen as an attached monitor.

Hardware Requirements

If you own two computers with separate screens you can use ScreenRecycler. Even your laptop can be used as second screen for your main machine. Both these computers need to be on the same local network. The software does work wirelessly, but there’s a noticeable lag when moving windows around on your additional monitor.

How Does it Work?

There are two steps for setting the system up. Firstly, you need to install ScreenRecycler on your primary machine (the one gaining an additional monitor). This process adds a new display driver to your system and, unusually for OS X installations, requires you restart your Mac. The second stage is to install JollysFastVNC on your old Mac (or a similar VNC client for Windows).

After everything is installed, opening both applications at the same time should automatically initiate a connection and add the new monitor as an available display in System Preferences:

Altering screen arrangement in System Preferences

Altering screen arrangement in System Preferences

You can move it around and change the resolution as normal. To ensure everything looks correct, set JollysFastVNC to display in Full Screen mode on your extra display. You should then be able to drag and drop windows onto your old monitor, just as if it was a locally connected display.

If you aren’t able to initiate a connection, try experimenting with firewall settings or changing the port number in the preferences window.

Speed & Performance

ScreenRecycler Preferences

ScreenRecycler Preferences

I tested the app on both a wired and wireless network, with performance on the former being vastly superior. There are a number of preferences you’re able to set to change quality and compression settings:

  • Scanrate covers how often updates are sent to your screen – the higher this setting the more CPU used to power your extra display.
  • Compression uses your local CPU more, but offers better performance on slower networks through transferring smaller amounts of data
  • Degredation is used automatically when the framerate drops below a certain level – you can experiment with different settings to reach a solution which ‘feels’ right.

I’m using my extra monitor primarily as a display for my to-do list and Twitter client – these are both apps which don’t update on a regular basis, so running the connection wirelessly is acceptable. Depending on your planned use, you’ll need to experiment with different compression methods and network setups.

My Setup

Here’s a quick snap of my desktop, extending my desktop to an old MacBook:


As with most application reviewed, we’ll be giving away a copy of ScreenRecycler in the next few weeks. Keep up to date via Twitter or RSS to be sure you don’t miss out!


I was thrilled to discover ScreenRecycler, and have found it to work great for my fairly basic requirements. It allows you to achieve a monitor setup which is otherwise not possible, and provides a great use for any dusty old machine you have lying around the office.

That said, if you don’t have a particularly fast network, using the additional screen for video intensive applications (such as watching a movie, editing photos or regularly flipping between apps) may create unacceptable lag. It’s worth experimenting, as the app is available as a free trial which requires re-connecting after 20 minutes of use.

Do you use a multiple monitor setup? I’d be interested to hear if you share my thoughts on the usefulness of screen estate along with any interesting methods you have for setting up such a system.


Add Yours
  • I have a 19″ external monitor that I use with my mac and I use spaces; so I’ve never really needed more than one screen because flipping through my “9” screens is just a Cmd + arrow away.

    Although this does look like a neat app and I’m sure a lot of people could make use of it.

  • Synergy works for me. I use it with 3 monitors and 4 computers (2 computers share one monitor through a kvm) and it works wonderfully for me. I can share clipboards and synch screensavers. It only worries about the mouse and keyboards so it has very good performance. And it’s free! Hard to beat that.

  • I use teleport and it is free. :)

  • You know. I really wanted to use this and I tried it with my old Windows Vista laptop, but I couldn’t get it to connect with any VNC, it was pretty upsetting. Since my old windows laptop sits around a lot, I thought I would be able to make some good use of it, but I couldn’t. Thanks for showing us!

  • I can recommend teleport by abysoft. It works like a charm and its free!

  • I have more Macs than I have space. :( Giving it a pass on this one.

  • I haven’t tried this app but I do believe that Teleport is better in some ways. It lets me use the same keyboard and mouse with two Macs.
    I have IRC, Twitter, uStream and iChat all on my iMac while using Safari, Adium and everything else on my MacBook Pro.

    Teleport doesn’t effect my CPU/RAM unlike what ScreenRecycler seems to do.. cause instead of sending all the apps and quite data heavy stuff over the network, you’re just sending keystrokes and mouse movements. – One downside is that you can’t drag apps from one to the other.. but I don’t really need to do that.

    Maybe you should look into Teleport and write about it.

    and here is a photo of my Set-up:

  • As I understand it, ScreenRecycler and Teleport serve completely different purposes.

    ScreenRecycler uses a second computer as an additional display for my main computer. The effect is that I get more screen real estate on the main computer. So I get two screens dedicated to my main computer, and can mouse between them, distribute app windows across both monitors, etc. Both displays show apps running on my main computer.

    Teleport lets me control two computers, each with their own physically-connected monitor, via a single keyboard and mouse. Each display is dedicated to the computer to which it is attached, and shows only apps from that computer.

    ScreenReclycler basically runs a VNC client on the second computer, and the app on the main computer acts as the VNC server.

  • I’ve been using SR for over a year and a half now. One of the best purchases I’ve ever made.
    At the time, I had a 13″ MB, and a really old 17″ PowerBook G4. Using SR gave me so much more screen real estate, it was great.

    Since, I’ve bought a 17″ MBP, but if I’m ever at my desk, I’ll still use the PowerBook for double the space.

  • Did anyone get this to work in combination with a PIII Windoze XP Laptop?