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PC's -- what's new?by Lee Alexander Are you thinking of buying a new PC? There are a few advances to consider. Step one is to decide what you want yo ur new PC to do. Broad categories include: Multimedia PC -- to handle music and video editing Home theater PC -- with surround sound multiple speakers and hardware that won't look out of place in a recreation room. Gaming PC -- with all the latest bells and whistles to show off the graphics of the newer games Budget PC -- today's low-cost computers outperform top-of-the-line units of just a few years ago. Business PC -- foregoes high-level features of the first three models but does not skimp on speed, memory, and storage.
Form factors -- cases to house the components of your PC, come in a variety of shapes and sizes: Full-Tower (21 to 26 inches tall), Mid-Tower (about 17 inches tall), Mini-Tower (15 to 19 inches tall), Micro-Tower (about 13 to 15 inches tall), All in One (many shapes and sizes, as in Apple's Macintosh), Slimline or SFF [small form factor] (less than 15 inches wide, three to 5 inches tall), and Compact (about the size and of a large shoe box) designed for portability among gamers and their LAN (Local Area Network) parties.
CPU's -- the two major manufacturers of microprocessors, AMD and Intel, have finally given up the ridiculous race for higher speeds. At around 3 GHz (Gigahertz - one billion cycles per second of electromagnetic energy), only a diehard gamer, dedicated to FPS (first-person shooter) games, would care if his CPU was 3.0, 3.4, or 3.6 GHz. For normal business and home use, there would be no appreciable difference in applications. Other factors, such as bus speeds, memory response, and peripheral storage devices would have a greater impact on application performance.
The new buzz for CPUs is Hyper-Threading, the sharing of computational task by double cores of CPU logic gates on a single die. The manufacturing processes have made the transition from micron to nanometers. Micron = 10 -6 meter (approximately 1/25,000 of an inch); nanometer = 10 -9 meter, a thousand times smaller. A human hair is about 80 microns in diameter. This does not mean that gate line widths (a ‘gate' is what turns a transistor on/off) were reduced a thousand fold. A steady progression of smaller and smaller photo resistive and etching processes reduced dimensions from microns to tenths of microns. Fractions of currency ($0.98) may be good marketing technique, but science prefers whole numbers like 90 nm, compared to 0.090 µ, the state-of-the-art today.
The first Pentium CPU by Intel contained about 3 million transistors; today, CPUs contain over 200 million transistors. One of the greater gains in performance was to install the L2 cache (pronounced “kash”) on the CPU die. Cache is from the French, meaning a secure place to store things. For the PC, it is temporary storage for almost instantaneous retrieval. Cache first appeared in a computer in IBM's mainframe System/360 Model 85 in 1968. Since then, almost all computers have included a form of cache. I mentioned moving L2 cache to the microprocessor die. For a long time there was a small cache, L1 (Level 1), on the die and a separate chip (IC, Integrated Circuit), the L2 cache, on the motherboard. Cache memory is made of SRAM (Static Random Access Memory), a more expensive element, than DRAM (dynamic RAM). The original Celerons, Intel's bargain-basement CPUs, were cache free, but now include both L1 and L2 caches, albeit of a lower value than Pentiums. For value based PCs, AMD's Sempron and Intel's Celeron families of CPUs are a good bet. These units now perform as high-priced Athlons and Pentiums did just a few years ago.
Intel's new generation of P4 chips is code-named Prescott . Unfortunately, the previous generation, code-named Northwood, without Hyper-Threading, will still be around for awhile. It will take some diligence to know what version you are getting. Versions include: Northwood P4 Extreme Edition with Hyper Threading, P4-EE; the new Prescott based P4 with Hyper-Threading which will have an E designation after the speed, for example P4-3.2E; and a Prescott-based P4 without Hyper-Threading with an A designation after the clock rating, such as P4-2.8A. The Prescott architecture doubles the L1 cache to 16 KB and the L2 cache to 1 MB. AMD's naming designation for Athlon chips forwent the speed rating for a number designating power capacity similar to Intel's speed rating. For example, an AMD Athlon 64 3200+ can compete with an Intel 3.2 GHz Pentium 4 with SSE3 (Streaming Single Instruction Multiple Data Extensions). That last feature simply means better handling of floating-point numbers.
Peripherals are logically external devices. Some examples are external hard drives, scanners, broadband modems, and even a digital camera when you have connected it to the computer. The most common peripheral is the printer. These devices communicate with the computer via a bus . For older computers, connection to peripherals was by way of a PCI bus (Peripheral Component Interface). Newer connections are via USB or FireWire ports. USB (Universal Serial Bus) comes in two models. Version 1 .1 communicates at a rate of 12 Mbps (million bits per second), while version 2 .0 is 40 times faster at 480 Mbps. FireWire or IEEE 1394 is another high-speed serial bus rated at about 400 Mbps. FireWire 800 (IEEE 1394b) is a recent version; however, few devices have yet to reach market. Regardless of its designation, don't expect FireWire 800 to run twice as fast as FireWire 400. In spite of USB 2.0's higher speed rating, compatible devices usually run faster on FireWire. Be aware that these are top speeds and are seldom reached in the real world. Of late, even printers have foregone the slower parallel port for faster USB connections. If you intend to use an older printer, be aware that there are PCs manufactured today without a parallel port.
The parallel PCI bus connecting the card slots within the PC is being supplanted by a faster, serial PCI eXpress bus and the latest hard drives have switched over to a serial ATA bus. This may seem counterintuitive, replacing broad parallel pipes with a single conduit; however, the technology is akin to using higher voltage with less current and higher (thinner) gauge wiring. By eliminating flat ribbon cables, cooling the interior of the case can be more efficient. Cooling fan diameters and speeds can be reduced, making for a quieter environment.
RAM - Random Access Memory - has undergone quite a few generations; from EDO (Extended Data Output) and the like, through RDRAM (Rambus, a very expensive version of RAM) to today's DDR-SRAM (Double Data Rate- Synchronous RAM). Your PC runs on clock cycles in the form of a square wave. The dynamic memory must be constantly refreshed and this was done on the upward ramp of the square wave. The DDR component refreshes the memory on both the up and down ramps, doubling the speed of the process. The motherboard must be tailored to fit the version of RAM in the computer. Older memory ‘sticks,' SIMMs (Single In-Line Memory Module), have been replaced by DIMMs (Dual In-Line Memory Module) with greater capacity and higher speeds.
Hard Drives -- the newest models are serviced by a serial ATA bus, as opposed to the older parallel ATA bus. ATA is the acronym for Advanced Technology Attachment Bus. Speed and capacity have increased dramatically, while prices have dropped by appreciable levels. The standard speed for desktop units is 7200 rpm, with 10,000 rpm units available at higher prices. Higher level PCs are using multiple hard drives in RAID (Redundant Array of Independent Devices) configurations, the most common being RAID 0. Also known as striping , the data is spread over both the discs. Other RAID configurations store data redundantly for security from disk failure.
Video cards -- these days, the high-end market is dominated by two manufactures ATI and NVIDIA I can't tell you which one is on top, because by the time you read this, the seesaw probably will be tilted to the other direction. The basic features of advanced video cards is the incorporation of a GPU (Graphics Processing Unit), which is meant to reduce the load on the CPU (Central Processing Unit, the heart of your PC) and on-card video memory. The capabilities greatly added to the enjoyment of RPG (Role Playing Games) such as Doom, Halo, and Half-Life 2. The cards can also enhance photo and video editing. Besides the hit on your wallet (the cards retail for about $500), power requirements and additional cooling are major factors. One top-of-the-line version required the space of two PCI slots.
Another technology destined to bite the dust is the AGP ( Accelerated Graphics Port ). Intel created this advanced interface with a single slot on the motherboard, just for the video card. The old PCI bus, at 132 Mbps, could stifle communication between the video memory and the rest of the computer. The first version of AGP doubled the speed to 264 Mbps. The current version of AGP is 8 X, with a broader bandwidth. AGP also provided the video card with a direct link to the system memory, RAM. Using DME (Direct Memory Execute), it could store graphical textures in both the video memory and the main memory. In spite of all these advances, PCI Express has been shown to be a superior technology.
Optical Drives -- there is no doubt about it, the floppy is dead; replaced by CDs, DVDs, and flash memory. From budget PC to top-of-the-line, you will definitely want an optical disk burner. For modest off-line storage and minimal backups, CDs are fine. For full content backup, videos, or large slideshows DVDs are the choice.
CD-ROM Compact Disc-Read Only Memory is a factory produced product, the data is unchangeable. CD-R is a one time, writable disk (CD+R is another format). Capacity is 700 MB. CD +/- RW is a rewritable disc upon which you can edit and erase files. Capacity is 650 MB.
DVDs (Digital Versatile Disc, no longer called Digital Video Disk) have a wide range of capacities, from 4.7 GB to 17 GB DVD-ROM
a replacement for CD-ROM with a capacity of 4.7 GB DVD
- RW DVD dash Rewritable. Introduced by pioneer
in 1999, it uses phase change technology to read, write, and erase
data DVD +/- RW, Dual Layer approaches 9.4 GB capacity.
On the horizon is a blue laser DVD burner. The laser wave length for CDs is 780 nm; for DVDs it varies between 635 and 650 menus. Shorter wavelengths mean smaller dots and pits, increasing areal density. Presently these burners are only available in Japan , and cost thousands of dollars. For the budget minded, a CD burner/DVD combo drive (it only reads DVDs) is a viable alternative.
Flash memory has essentially replaced the floppy. Capacity ranges up into gigabytes of storage, albeit with sky-high prices. The devices come in basically two forms: small cards and key ring models. The card and an attendant card reader can perform double duty with digital cameras, PDAs (Portable Digital Assistants), and other handheld devices. Multiple card format readers are available and many PCs and photo printers now come with built-in card readers. Later BIOS (Basic Input/Output System) software allows for boot up from flash memory.
Audio -- a wide latitude of systems is available for this feature. From simple two speaker stereo through an 8.1 surround-sound set up, some arrangement should satisfy casual users through audiophiles. The ‘.1' in a system indicates a separate bass woofer; thus an 8.1 system consists of eight satellite speakers and one bass woofer.
As you can see, choosing the works of a PC is not a trivial task. Perhaps a good way to start is to see what the OEM's (Original Equipment Manufacturer) such as Dell, Gateway, and Hewlett-Packard build as representative models. From such a beginning, choosing components to suit your budget and needs is a very personal undertaking. From OEM to local mom-and-pop shop, there is no need to compromise or pay for features that you will never use. Technologically, the useful lifetime of PC is relatively short, about three years. Your personal computer is what you make it. Just be aware that there is a point where upgrades and additions are no longer financially viable.
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