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How To Buy
Access time refers to the amount of time it takes the drive to find specific data on the CD-ROM and then read a small block of information from the disc. Access times improve as data-transfer rates go up. With a 12X drive, expect access times of under 125 milliseconds.
Speedy data-transfer rates translate into smoother display of video and animation. The earliest CD-ROM drives were called single-speed or 1X readers. As the state of the art evolved, the speed of each new generation of drives was described in relation to those early devices, with 1X becoming the baseline. A 4X drive was four times that speed, and so forth. Today, the fastest CD-ROM drives on the market are 12X and 16X devices. The 12X drives, which are more readily available, can transfer data at a rate of 1800KB per second, while the single-speed drives were clocked at 150KBps.
Data Buffer/Cache Memory
Buffer sizes range from about 32KB to 256KB. CD-ROM drives have firmware that tries to anticipate which data on a CD-ROM will be accessed most often; it then stores the data in the buffer to expedite the supply of information. A larger buffer is usually better, but how efficiently a unit's drivers use the buffer is important, too.
Prices for a 12X CD-ROM drive can vary greatly, depending on the interface and product specifications. Expect to pay anywhere from $150 to $250 for an Enhanced IDE (EIDE) drive. SCSI drives will cost more, from $250 to $500. Add the cost of a SCSI interface card ($100 and up) if you don't already have one. An external drive will cost anywhere from $50 to $100 more than an internal unit.
Most drives give you a choice of interfaces. Many users, especially if they're replacing a drive, will opt for EIDE, because it's easier to install and less expensive. A SCSI interface is a high-performance alternative, but it requires a SCSI interface card. If you do install a SCSI card, you can link up to seven peripherals to it.
Just a couple of years ago, a 2X or 4X CD-ROM drive seemed pretty fast. But bigger applications, graphics and other multimedia file types will likely push those drives to their limits. When you play games, you may notice the graphics tend to run jaggedly, and scene switches take a long time. If you work with large databases, finding the data you need may be testing your patience. If so, it's time to consider upgrading your CD-ROM drive. A 12X drive is both available and affordable.
Today, most drives use a tray-loading mechanism rather than a caddy. If you work in harsh environments or just want to ensure that the information on the CD is safe, a caddy is a good choice. But tray-loading models tend to be less expensive and more readily available. Many drives offer front-panel controls, so that you can manage the drive manually as well as through software.
When faced with a shelf of products with almost identical specifications, making a final decision can be tough. Sometimes it's the "little things" that can help you make up your mind. For example, if you're considering a CD-ROM kit, make sure the appropriate cables are included. And look for a one- or two-year warranty backed by toll-free support.