Buying a PC is no simple task these days. Do you want a system with the fastest processor or the biggest hard drive? What are your wireless options? How do you choose from all those optical drives? If you don't know your CPU from your USB, the whole process can be maddening and time-consuming. Fortunately, many manufacturers today offer PCs that are tailored specifically to the needs of small businesses, making the buying process a lot easier. Even so, before you begin to shop, take the time to brush up on the core hardware specifications. This easy-to-use primer will fill you in on today's essential hardware-related terminology.

Processor ABCs
Key terms here include the clock speed, which is the speed at which the CPU (central processing unit) executes instructions. Clock speeds are expressed in MHz (megahertz) or GHz (gigahertz). Bandwidth refers to the number of bits processed in a single instruction. Check out the levels of cache memory in the computer. If the CPU can find the data it needs for its next operation in cache memory, it will save time compared to having to get it from RAM. L1 is Level-1 cache memory, usually built onto the microprocessor chip itself. L2, or Level-2, cache memory resides on a separate chip (or expansion card). The front-side bus is the speed at which the CPU communicates with main memory (so the faster the better). Hyper-Threading enables an Intel microprocessor to execute two (rather than one) concurrent streams (or "threads") of instructions sent by the operating system. Does the PC contain a copper microprocessor to connect transistors? Copper is a better conductor of electricity than aluminum, the metal used in most chips. Copper chips offer faster performance and lower power consumption and are smaller.

Cutting-edge 64-bit processors have been getting a lot of press lately. Intel's Itanium processor breaks from the longstanding 32-bit x86 architecture, while AMD's new Opteron chip extends the life of the x86 architecture to 64 bits. In the latter case, that means both 32- and 64-bit applications run at full speed on Opteron-powered hardware.

Memory matters
RAM (random access memory) is the place in your PC where the operating system, the running applications, and open data files are kept. More RAM allows you to run more programs simultaneously and to handle larger data files. Three types of RAM are commonly used.

• SDRAM (synchronous dynamic RAM). The most common form of desktop memory used today, SDRAM is synchronized with the CPU's clock, so there is little or no downtime when transferring data to the processor. SDRAM is available in 8MB to 256MB DIMMS (dual in-line memory modules).
  
• RDRAM (Rambus dynamic RAM). Some of the fastest system memory available for desktops, RDRAM transfers data at up to 600MHz. RDRAM is currently available in modules of up to 256MB.
  
• DDR (double data rate) SDRAM. Similar to SDRAM but twice as fast. Data is accessed two times per clock cycle as opposed to standard memory, which accesses data once per cycle. DDR memory is available at speeds of 200MHz and 266MHz in 64MB to 1GB DIMMs.

The important thing to keep in mind is that you cannot mix SDRAM, Rambus, and DDR SDRAM on the same motherboard. If you plan to add memory to a PC, choose the specific type intended for your motherboard. (SDRAM modules each have 168 pins, while Rambus and DDR SDRAM modules have 184 pins.)

Put it in storage
The PC's hard drive is a type of disk storage that stores and retrieves digital data from a magnetic surface. A hard disk is generally accessed over one of a number of bus types, including ATA (Advanced Technology Attachment, also called IDE), SCSI (Small Computer System Interface), FireWire and Fibre Channel. Beginning in late 2002, Serial ATA was introduced to improve upon the performance of ATA.

Three main factors that determine hard drive performance: seek time (the speed with which the drive can position its read/write heads over any particular data track), latency (the time that elapses between the moment when the read/write head settles over the desired data track and the moment when the first byte of the required data appears under the head), and data transfer rate.

Note: The cardinal rule of mass storage is: Don't skimp. The difference between a 20GB and a 40GB hard drive can be as little as $50 when you order your desktop, so configure your system with as big a drive as your budget allows.

Optical options
The most common forms of optical drives are CD-ROM and DVD-ROM. Most desktops today ship with at least one of the two. The latest addition to the optical drive family is the so-called combo drive, which integrates several different optical drives into one device.

Optical discs offer numerous advantages over magnetic storage media, the foremost being that they hold much more data. Emerging technologies, such as Blu-Ray, offer up to 27 GB (gigabytes) on a single-sided disc. In comparison, a floppy disk can hold 1.44 MB (megabytes).

• CD-ROM. These are used for installing software and playing CD-based audio and video media.
  
• CD-R. This works as a CD-ROM drive but can also write to CD-R media. CD-R drives are popular for burning audio CDs, which can be played back on any CD player. CD-R media can be written to just once.
  
• CD-RW. CD-RW drives are similar to CD-R drives but allow recording to CD-RW media, which can be erased and re-recorded. CD-RW drives will read standard CD media, but older CD-ROM drives may not be able to read CD-RW media.
  
• DVD-ROM. This is a read-only drive that supports DVD media, which are the same size as CDs, but recorded on both sides and capable of holding far more information.
  
• DVD-R. This is a DVD drive with the ability to write to DVD-R media. DVD-R discs are write-once media
  
• DVD-RAM. Like ordinary RAM, DVD-RAM can be repeatedly read, written to, and erased. Intended mostly for removable computer storage, DVD-RAM provides the capabilities of CD-RW. But with a storage capacity of up to 9.4 GB per double-sided disc, DVD-RAM has many times the capacity of CD-RW.

And don't forget ...
Bluetooth is a new technology for wirelessly transferring data short distances (up to 30 feet) among notebooks, cell phones, Palm or Windows CE handhelds, and printers. It is also built into a few current notebooks.

802.11 is the emerging standard for wireless networking. With this technology, anyone within about 50 to 100 feet of an Ethernet wireless access point can connect to wired networks and the Internet at a high speed.

USB (Universal Serial Bus), an all-purpose input/output connector, supports data transfer rates of 12 Mbps. A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards.

XGA (Extended Graphics Array) is the most common screen resolution for desktops and notebooks: 1,024 pixels (dots per inch) horizontally by 768 vertically.

Be sure to keep this article handy when shopping for new hardware for your small business. It may prove to be a helpful reference for deciphering the jargon and terminology used to describe hardware features.