24 CD-ROM Drives: Double-Speed Rules

Today's mainstream CD-ROM drives offer faster performance at the most economical prices ever. We'll tell you which one is right for you.

Chandrika Mysore

CD-ROM drives used to be a fancy option for your desktop system. Today, they're essential for loading new application software, viewing presentations, or accessing commercial and private sources of data. Recognizing this trend, many system vendors offer CD-ROM drives in ``multimedia'' bundles. As we went to press, Gateway 2000 announced that all its systems would include a CD-ROM drive standard.

But you don't have to buy a new system to take advantage of CD-ROMs: This lab report evaluates two dozen fast and easy-to-install external drives that can serve you well whether you use a PC or a Mac. We tested 20 SCSI-based, desktop drives and ranked the best for general-purpose, low-cost, and text-intensive applications. All but one of the drives was double-speed, with throughput scores of 300 to 350 KBps. The remaining drive was NEC's quadruple-speed MultiSpin 4X Pro, which was the most expensive drive we tested ($995) but also the fastest for throughput: 590.3 KBps. We also ranked four portable drives that connect via a SCSI and/or a parallel-port interface.

While this report focuses on external drives, you can gauge performance of drives offered by system vendors by looking at the ``Roll Call'' on page 186, which lists the basic drive mechanism used in each product.

Double-speed drives have claimed their place in the mainstream market because of price and performance that's fast enough for them to display full-motion video in some resolutions without dropping any frames. Less-expensive single-speed drives of the recent past offered only 150-KBps throughput with mixed reviews for video performance.

To rank drive performance, we used custom benchmarks to measure sequential throughput, random-access time, and CPU utilization of each drive. We also ran application tests, including a 912-frame video sequence to gauge if individual frames were dropped. Keyword and Boolean text searches helped us determine which drives were best for searching large text databases.

Although NEC's quadruple-speed drive was the only one available for our test cycle, you can expect several other vendors to offer these faster drives by the time you read this. Note that IBM also sells CD-ROM drives, but it didn't participate in this report because it expected to introduce a new model late this summer.

How to use this guide

Turn to page 179 for details on the double-speed drives that showed the best performance, features, ease of use, and price for Best Overall, Low Cost, and Text applications. The text box on page 182 ranks four portable drives.

Drive price, which doesn 't include the adapter. Adapter prices for each drive are listed in the ``Roll Call'' on page 186.

Lower numbers indicate faster performance. This score represents how fast the drive can read data spread across the CD.

Lower numbers indicate better performance. This shows the percentage of the time the computer's CPU was used by the CD-ROM drive during a sequential read at 150 and 300 KBps.

Higher numbers indicate faster performance. A measure of the amount of data a drive can transfer in 1 second.

We considered the quality of documentation, installation, and user interface, among other factors.

Better ratings indicate drives with longer warranties, a range of device drivers, and support for a greater number of modes, including CD-ROM XA (Extended Architecture), multisession Photo CD, and ISO-9660.

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Illustration: Choosing a CD-ROM Drive Drive speed, the rate at which a drive can transfer data, is determined by a number of factors, including spindle rate and how effecti vely the drive uses its buffer. Double-speed drives are good choices for most general-purpose applications, and excellent models exist that range from about $300 to $500. Quadruple-speed drives offer faster throughput but sell for $1000 or more. FRONT PANEL At a minimum, this should include a ``CD busy'' signal, a power-on indicator, a CD eject button, an emergency manual-eject hole, an audio jack, and volume control. SCSI CONNECTION For best performance, choose a SCSI drive. Drives with parallel-port interfaces posted slow throughput scores and are generally unacceptable for displaying full-motion video. They are solid choices for portable applications that don't require video, however. If the drive comes with a standard SCSI connector, you'll be able to attach other SCSI devices to that adapter. Some drives offer only a proprietary SCSI connection, which can't support other SCSI peripherals but may show some performance advantage. STANDARDS SUPPORT For the greatest flexibility, make sure the dri ve you buy can read multisession CDs, supports MPC Level 2, and supports CD-ROM XA (for details, see the glossary on page 182). CD LOADER We find tray loaders (pictured) to be easier to use than caddies, although this tends to be a subjective decision. Caddies can be an advantage if they serve double duty as CD loaders and storage cases, in which case, you never have to expose the CD to dust.