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.