DVD-ROM drives in PCs have long since overtaken their CD-ROM equivalents in popularity. It's rare to find a new PC that doesn't ship with some form of DVD drive in it. Should you be stuck with a CD-ROM drive and want to upgrade it to a unit that simply reads DVDs instead, it's a very simple task. A bog-standard DVD-ROM drive sells for around £30-40, or you can now get combo drives, which add CD burning capabilities too. Note that a DVD drive will also happily read CDs. Look for a unit that can read at 16x and you should be fine.

DVD writers used to be a murkier area, with several formats competing for your money. In recent times, however, multi-format drives have emerged that get round this problem. We'll get to them shortly.

Unlike CD burners, where you have one standard (CD-R/RW) and thus little hassle, the DVD burning market has gone three ways; DVD-RAM, DVD-R/RW and DVD+R/RW. DVD-RAM is the easiest one to rule out, unless you're looking to do large scale data backup only. It's not really of much appeal to the consumer, because of lack of compatibility with home DVD players, and has found a happier home in a corporate environment. Panasonic is the biggest name championing this format.

DVD-R/RWs work in a similar way to CD-R/RWs, and this tends to be the most economical format. Championed by the likes of Pioneer in the early days, it's the 'official' format of The DVD Forum, a group that devises the standards for the overall DVD format. Technically, it's arguably not as strong as the DVD+R/RW format, yet is likely to suit the needs of the vast majority. Discs produced in DVD-R/-RW will happily play in your household standalone DVD player too.

As will discs written in the DVD+R/RW standard, a format championed by the DVD Alliance (attracting the attention of the likes of Sony, Yamaha and Hewlett Packard). It's technically the superior format, primarily because it rewrites more efficiently than its DVD-RW counterpart. However, because it came out of the traps last, it's not the most widely used. After all, Betamax was a better format, but it was VHS that people adopted, although the winner isn't as clear cut in this case.

The easy way to circumnavigate all this, though, is to buy a drive that supports both the '+' and '-' formats. These 'combo' drives are availble for under £100, and are being made by most of the main drive manufacturers. This also means you don't have to fuss over getting the right blank media (-R media, for instance, won't work in a +R drive).

Which just leaves us with the matter of speed. Don't be fooled into thinking that just because a DVD drive has a write speed of 2x, it's an awful lot slower than a CD burner that writes at 32x. In this instance, the DVD drive actually writes faster. Bascially, a DVD burner writing at 1x can burn nearly 1.4MB in a second, whereas a CD burner at 1x manages under 0.2MB in the same time frame. Incidentally, DVD burners can also burn CDs, but tend not to be able to manage the speeds that a dedicated CD burner could rack up.

Finally, when choosing what speed of drive to buy - and at the time of writing they go up to 8x - you should note that it's crucial to marry up the drive with the blank media. Having an 8x drive matters not a jot if the media you write to only supports 2.4x. It'll work, just at the speed the media dictates.