On the spec sheet, the VW223B seems unspectacular. There's a VGA interface, internal speakers and USB hub. But that USB connector isn't an ordinary connector. After installing ASUS’ EzLink driver, that port becomes a graphic adapter. This makes it any easy way to connect two full-size displays to a PC with a single graphics interface or to a notebook computer.

We have to say, video over USB didn't exactly inspire lots of confidence. Simply, we weren't certain that USB would be able to deliver enough throughput to support a decent video signal. However, we were pleasantly surprised although there are some limitations.

If you plan to use the VW223B over its VGA connector then there's no software needed. However, if you plan to use the EzLink Display to connect the screen via USB there's a simple driver installation to go through that requires a reboot. Once we did that, we connected a VW223B by USB. The driver then allowed us to choose between an extended desktop and screen mirroring at the full 1,600 x 1,050 resolution.

We tested the VW223B using Passmark's MonitorTest. Over the VGA interface, we found that colour quality with arcs and diagonals displaying with minimal jaggedness. Over the USB connection, we couldn't see any difference in these tests.

Part of one of MonitorTest's test screens has a dense pattern of tight black and white stripes. The VGA connection exhibited some noisiness with this pattern whereas the USB connection displayed this pattern perfectly. In contrast, the moire test, while a little noisy with the VGA interface, was a disaster under USB. Simply, the USB interface couldn't push the pixels fast enough.

The advantage of having a USB interface is that it's easy to set up a dual display system. We tested the VW223B with a number of desktop applications and it was able to deal with them quite well although it was noticeably slower than the VGA connection. We ran a pair of VW223Bs adjacent to each other as a two-head system and, for office apps, they were good enough. The USB interface was not satisfactory for DVD playback or gaming.

Positioning the VW223B will have you looking for the phone books as there's no height adjustment. While there's a reasonable range of tilt the screen can't be rotated from landscape to portrait. For a display that is pitched at those looking for an easy way to move to dual screens this is a significant omission.

If you're looking for a high performance, fully featured display then we're not sure that the VW223B will fit the bill. However, the ability to us a USB port to support dual screens means that the VW223B could find a place on many desks.