Choosing hardware: what you should know
By Edward Doyle
For physicians looking to upgrade their computer, it is a confusing world. What physicians really need from a computer depends on how the machine will be used—from simple word processing to electronic medical records with images—and the environment in which it will be used—part of a network or as a standalone unit. Even so, there are some general guidelines to ensure that the purchase meets current needs and is flexible enough to accommodate foreseeable ones. Much of the following advice is from informatics presentations at this year's Annual Session in San Francisco.
PC vs. Macintosh. The first stumbling block for many physicians is whether to buy a Windows-based machine (also referred to as a PC) or a Macintosh. Some experts insist that while there are clearly more programs for PCs, most people will only use three or four applications—word processing, spreadsheets, electronic billing and literature searching, for example—and they will be able to find at least one program for whatever type of computer they choose. While that is generally true, buyers should look for software they think they will use—electronic medical records, for example—and see how many vendors offer products for both PCs and the Macintosh. In addition, buyers need to consider what kind of support is available for either platform. If you purchase a Macintosh instead of a PC, will your institution provide technical support? Will you be able to talk to your colleagues about minor problems, or are they all using PCs?
Speed. The next decision is speed. First consider the computer chip itself. For PCs, computer chips are ranked in numbers; older 386 chips are obsolete, and even 486 technology is becoming out of date. The Pentium chip, the equivalent of a 586 chip (the name was changed to Pentium for copyright reasons), is now the industry standard. Pentiums are twice as fast as 486 machines and 20 times faster than 386 machines.
The newest computer from Macintosh, the Power Macintosh, uses a reduced instruction set computing (RISC) chip. The Power Macintosh, also known as the PowerPC, runs about as quickly as a Pentium.
Another factor that determines how fast a machine will run is its processing speed, rated in megahertz. Processing speed is critical; a 486 chip running at 100 megahertz, for example, can be nearly as fast as a Pentium chip running at 60 megahertz. The Power Macintosh is commonly offered in 75, 120 or 150 megahertz models.
While you can run most medical software using a machine with a 486 chip, Pentiums will run these applications much faster. Most experts suggest purchasing a minimum of a 90 megahertz Pentium.
As far as Macintoshes go, the Power Macintoshes offer various amounts of RAM and processing speeds. Generally, the higher the model number, the faster and more powerful the machine.
Storage space. Technology for disk drives, the devices that actually store data while it is not in use, is similar for both PCs and Macs. While machines with 500 to 750 megabytes will hold most users for a while, count on needing at least one gigabyte (1,000 megabytes) or more of hard disk space.
Memory. Random access memory (RAM) also affects overall performance. RAM is rated in megabytes for both PC-based computers and Macintoshes. Most Power Macintoshes come with 16 megabytes of RAM, which is enough for basic uses. Experts say that adding up to 32 megabytes of RAM will allow users to run more programs at once and improve performance.
Many PCs come with four megabytes of RAM, but you should plan on having at least eight. You'll need 16 megabytes to run software like Windows 95 comfortably. You may want to buy a machine that can accommodate up to 64 megabytes of RAM if you're considering purchasing a practice management system or other bulky software down the road.
Vendors are also adding cache memory, small blocks of high-speed memory that allow a computer to store bits of the most commonly used information. Because data can be more quickly retrieved from the cache than from RAM, cache memory greatly improves a computer's performance. The rule of thumb for PCs is that for every 256 kilobytes of cache, computer performance increases about 20%. Cache memory ranges from 128 kilobytes on low-end PCs to 512 kilobytes on high-end machines. Macintoshes also use cache memory, although the quantities vary slightly.
Monitors. The more dots or pixels that appear on the screen, the higher the resolution and the better the detail. For PCs, video graphics array (VGA) monitors divide the screen into 640 pixels horizontally by 480 pixels vertically. For better resolution, look for a super VGA (SVGA) monitor, which offers 800 by 600 pixels. Macintoshes offer a wide variety of resolutions but no one standard, though the same advice—the more pixels the better—holds.
Dot pitch affects the clarity of images, and less is better. In a 15-inch monitor, dot pitch should be no greater than .28 millimeter. Greater dot pitch—.40 millimeter, for example—lowers a monitor's price but is tough on the eyes.
Modems. Modems, which link a computer via telephone lines to the Internet and commercial online services like CompuServe, are rated in bits per second (bps). The faster the modem, the better, since many online services charge an hourly rate. Fast modems today operate at 28,800 bps.
Working online is expected to become even faster with the growing popularity of integrated services digital network (ISDN) technology, which will run at speeds of up to 128,000 bps. To use ISDN, you may need a different form of wiring into your home or office—check with your local telephone company for availability. Fees are dropping, but there are installation fees and hardware requirements that can easily cost hundreds of dollars. In addition, expect to pay a monthly fee of about $25. For physicians who use the Internet or other online services regularly, however, this increase in speed may be well worth the price.
CD-ROM drives. When purchasing a CD-ROM drive, there are three critical factors:
- "Access time" refers to how long a CD-ROM drive takes to locate a piece of information (text or images) on a CD-ROM title. Today's fastest drives can locate information within 150 to 300 milliseconds. (In comparison, computer hard drives can access information in under 10 milliseconds.)
- "Transfer rate" refers to how quickly a CD-ROM drive can move data from the drive to the computer once it has been accessed. Transfer rates are ranked by numbers; quad speed or 4x speed drives are considered adequate for most applications, but 8x speed drives are currently available.
- "Cache size" refers to the amount of text and images that a CD-ROM drive can store in its memory. CD-ROM drives with between 64k and 128k of cache memory are adequate, but machines with 256k caches perform even better.
The combination of access time, transfer rate and cache size determines a CD-ROM drive's speed. A 4x drive with a fast access rate and large cache could easily offer faster performance than a 6x drive with a slower access rate and smaller cache.
General tips. On the PC side, the advice from many experts is to purchase as many peripheral components (CD-ROM drives, fax/modems, etc.) pre-installed as possible. Otherwise, expect to spend the better part of a day installing these devices. Let dealers install add-ons like CD-ROM drives; veteran computer users say it will cost a little extra, but will be faster. Plus, the dealer—not you—will be responsible for any problems. (Installing add-on devices is fairly easy with the Macintosh.)
As far as where to buy, mail-order houses offer good computers at great prices, but it is more difficult to return a product for repairs and vendor support is not as good, according to published consumer surveys.
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