If you have a desktop PC which has no DVD rewriter, you have two options. You can either open the case and fit an internal drive, or plug-in an external USB device. If you have a laptop, only the second option is available and that's where this new rewriter from Lite-On comes into its own.

Based on a notebook-style drive, with a post-in-the-slot mechanism, the SLW-831SX can read and write both DVD+R and DVD-R discs, plus their rewritable counterparts, as well as all varieties of CD. It'll handle dual-layer (DL) DVDs, too, so you can burn discs of up to 8.5GB.

Connecting the drive up isn't quite as simple as you might imagine, as it requires external power, as well as its USB 2 connection. This is a shame, as it makes the drive portable rather than fully mobile: you still need a mains socket to plug it into.

The drive is fast for a laptop-style device, but slow compared with a 5.25-inch rewriter. To test this, we used a varied basket of files ranging in size from 10KB to 500MB and wrote them to a variety of DVDs, before reading them back to hard disk.

On DVD+R media, where the drive is rated at 8x, we wrote the files in just under three and a half minutes and read them back in just over three. On DVD+RW discs, again rated at 8x, read and write times were again around three and a half minutes, but on a dual-layer recordable disc, times were considerably extended, taking over six minutes in some cases. The rated drive speed drops to 2.4x on rewriteable media.

Lite-On has bundled a good software suite with the drive, including full versions of Nero Express and Power DVD. Between them, these two applications can handle most of the things you are likely to want to use the SLW-831SX for. Nero provides archival and backup - including scheduled backup - and compilations of all kinds of audio. Power DVD handles any DVD movies you want to show.

The ideal user for this device is someone who carries a notebook to and from work and needs the high storage capacity of a DVD rewriter. A desktop user would generally be better off with a less expensive internal drive.

This is an easy to use DVD rewriter which can read and write virtually any silver disc. It's a shame that it needs a separate power supply, or it would be fully mobile. If you just need a portable rather than a mobile drive, check out 5.25-inch external drives, which can be faster and cheaper than this Lite-On device.