Dual Monitors on a laptop

I yield to no-one in my enthusiasm for using dual monitors – once you’ve used them for a week or so, there’s no going back.

However – it’s not always simple to get the hardware sorted. Modern desktop PC’s mostly come with two video sockets on the back (usually one SVGA and one DVI) but older machines and laptops do not. A client of mine encountered a problem with the low-profile desktop PC’s they were using – they didn’t have dual ports, and they also didn’t have the internal capacity to accept a 3rd-party video card without an add-on riser that had gone out of production (for a few PC’s then you could probably find some on eBay, but several hundred?)

The answer to all of these problems is the same – an external dual-display adaptor.

There are two kinds – USB-attached and video-attached.

The USB-attached kind is a little box of tricks (about the size of a pack of cigarettes) with a USB cable on one end, and a SVGA port on the other. You plug monitor 1 into the computer’s normal video port, and monitor 2 into the adaptor. Special drivers then tell the PC to send video data via a USB socket, and the adaptor converts it back for the screen to use.

They work well, but the maximum data-speeds of USB place a limit on the resolution, colour depth, and/or the refresh rate of the second monitor. If you’ve got 20″ LCD panels or bigger – the overall result can be less than perfect.

There are lots of suppliers for this technology – a good example, however, is the Kensington product.


This will cost about £50.

If you have a need for larger screens, with higher resolutions, then the Matrox video-attached DualHead2Go device can help. It delivers better performance – and handles higher resolutions. Cost is about £150. You plug it into the PC’s video port, and plug both monitors into the adaptor (which is basically a video-card in a box with special drivers). Matrox do analogue and digital versions (and the digital version supports higher resolutions – DVI only though). The device takes power (but no data) via a USB lead, so no power-brick is needed. I plug that into a USB socket on one of the monitors, although that does feel a bit incestuous for some reason.

The Matrox can be set up to fool the PC into thinking it has two screens, but you can also configure the driver to treat the two screens as a single wide monitor. This means you get the windows taskbar across BOTH screens – something that can be very usefull.


The ‘DualHead2Go’ supports two outputs, and the ‘TripleHead2Go’ supports…well, you get the idea.

I have two 21″ ViewSonic VP201 screens attached to my laptop in the office – and I use the Matrox. I can’t fault it.