Don't fall for the marketing hype. The truth is that nearly any PC running a 600MHz or faster processor is adequate for most purposes, and a processor that runs at 1GHz or thereabouts is sufficient for all but the most demanding tasks. In difficult economic times, it's sensible to make do with what you have rather than replace it with a new system. That's true whether you have a corporate fleet of hundreds of PCs or just one or two PCs at home. But it's also true that making some inexpensive upgrades to your current system can extend its useful life significantly.

I recommend the following guidelines when upgrading PCs:

Here are the three most popular and cost-effective upgrades for older systems:

Adding memory is the single most cost-effective upgrade for most older systems. Memory prices fluctuate daily but, even at their highest, memory is cheap in absolute terms. Even if your motherboard has no free memory slots, memory is inexpensive enough that it's little hardship to replace some or all of the current memory with new modules.

Many older systems have 64MB or less, which is at best a marginal amount of memory for running current operating systems and applications. Upgrading a Windows 9X system to 128MB and a Windows 2000/XP or Linux system to 256MB or more can increase performance noticeably, particularly if you keep many windows open or if you run memory-hungry applications.

Hard drives in older PCs typically run at 3,600 to 5,400 RPM, much slower than current 7,200 RPM units. Installing a new 7,200 RPM hard drive can boost system performance noticeably, particularly for disk-intensive tasks, such as database searches. You'll also find that programs load, and data files load and save, in about half the time. The other benefit, of course, is that even the smallest current hard drives have much larger capacities than the largest drives sold two or three years ago. Current hard drives are inexpensive, too, with high-capacity models selling for as little as $1.00 per GB. Seagate and Maxtor IDE drives are fast and reliable. We prefer them to some other brands with which our experience has been less satisfactory.

Few older systems have anything more than a CD-ROM drive, because DVD- ROM drives and CD writers were expensive components when those systems were made. Nowadays, a good DVD-ROM drive costs $50 or so, and top-notch CD writers sell for $150. Replacing an old CD-ROM drive with a DVD-ROM drive allows you to read the increasing number of software distributions, games, databases, encyclopediae, and other materials supplied on DVD-ROM. Although corporate PCs seldom need them, CD burners are one of the easiest and most useful upgrades for a home or SOHO PC. Besides allowing you to duplicate commercial CD-Audio discs and program CDs, a CD burner provides a fast, inexpensive, and reliable means of backing up your data.

If you need a DVD-ROM drive, choose the Hitachi GD-8000 or the Toshiba SD- M1612. For a CD writer, choose one from the Plextor PlexWriter series, which are available in various speeds but are otherwise similar except for price. Better yet, buy one drive that does it all. The Plextor PlexCombo 20/10/40-12A costs little more than a standard CD writer, but adds DVD-ROM support. The PlexCombo reads CDs at 40X and DVDs at 12X, writes CD-R at 20X, and rewrites CD-RW at 10X. We now consider it the standard optical drive for mainstream and higher systems, and an excellent choice for upgrading an older PC.