Save money and gain features with a PC that has a chip from AMD or Cyrix, but beware: Market uncertainty makes bucking Intel a risky venture

By David Essex

Special to GCN

Intel Corp.'s competitors in the market for PC-standard x86 CPUs have been on such shaky ground of late that any guide to the chips will be short on product lists and long on speculation.

It must also focus on inexpensive to midpriced computers, the only type of Intel alternative currently available until the new Athlon K7 from Advanced Micro Devices Inc. debuts in systems later this summer (see story, Page 47).

One of the best-known names, Cyrix Corp., nearly dropped off the list when its owner, National Semiconductor Corp. of Santa Clara, Calif., announced in May that it was exiting the PC processor business. But a Taiwan chip set maker, VIA Technologies, now says it intends to buy Cyrix and keep Cyrix's MII chip alive. National Semi, meanwhile, will retain ownership of Cyrix's MediaGX chip but will only market it for use in so-called embedded systems, such as TV set-top boxes and handheld computers.

The status of another chip still sold in systems, the WinChip, is being re-evaluated while its maker, Integrated Device Technology Inc. of Santa Clara, Calif., looks for a partner. The company asked that its WinChip C6 and WinChip 2 CPUs be excluded from this Buyers Guide, though PCs containing the chip are still being sold.

Yet another contender, Rise Technology Co., has manufactured low-cost CPUs in quantity but has yet to announce a system maker that will use them.

That leaves AMD, also suffering from financial problems but still the only serious competition Intel faces. AMD's K6 series has been popular in home and small-business PCs; in January, K6s even outsold the equivalent Intel chips in U.S. retail stores.

Market turmoil aside, there are differences among the price and performance levels of Intel's Celeron, Pentium II and Pentium III chips and their non-Intel equivalents. A few rules of thumb can help you wade through the confusing array of features.

Clocking dollars

CPUs nowadays are most easily distinguished by their clock speeds, along with the size and number of memory caches, the type of specialized graphics instructions the chips contain, and the width and speed of the system bus leading from them. These factors determine the quality of performance for certain types of software applications, which, when balanced against price, provide a pretty good guide to purchasing the right CPU for your needs.

If users will be running large, compute-intensive, memory-hogging programs such as databases or high-end graphics software, it's generally best to buy a processor with the fastest clock speed you can afford. But clock speed alone doesn't determine performance; another major factor is the presence and size of the Level 2 cache, a nearby area of superfast RAM that the CPU uses to store frequently accessed data.

Intel's very first Celeron chips lacked a Level 2 cache; as a result, its performance was about 15 percent slower than that of comparable, but cache-equipped, CPUs. The newer Celerons have a secondary cache, but the lowest-cost chips, including Cyrix's MediaGX and IDT's WinChip 2 and C6, do not. Generally, more cache means better performance, and 256K or 512K Level 2s are typical of the highest-priced PC chips. Caches inside the chip itself can also improve performance.

With the advent of multimedia PCs and the Web, CPU vendors have dedicated special logic circuits, or instructions, to the complex calculations required to process large graphics files and videos. Intel was the first to do it with its 57 MMX instructions added to the Pentium in early 1997.

Last year, AMD followed with 3DNow for its K6-2 chip, which augmented MMX with 21 new floating-point instructions optimized for three-dimensional graphics. Intel only matched 3DNow this year with its Streaming SIMD Extensions (SSE, until recently known as KNI), a set of 3-D instructions included in Pentium III chips.

The new graphics instructions are exploited by just a handful of business applications, such as Adobe Photoshop and IBM Corp.'s ViaVoice speech-recognition software'3DNow's impressive software list is dominated by game developers. PC makers, however, are starting to use the instructions for software-only DVD decoding and for modems.

System buses are also key performance factors. he current high-end standard, 100 MHz, clearly contributes to better performance over previous-generation, lower-priced systems with 66-MHz buses. Intel plans to introduce a 133-MHz bus later this year, and AMD's upcoming Athlon has a 200-MHz bus. But both will remain underused until a new generation of faster memory arrives next year.

Independent benchmark tests designed to compare performance generally show AMD chips matching that of equivalent Intel products. Chips from Cyrix, IDT and Rise Technology also typically match the overall performance of their Intel equivalents, especially in graphics.

But delays in technical innovation and obstacles to mass production have prevented rival companies from keeping pace with Intel as the processor giant introduces next-generation chips that provide superior performance for the same money.

Some benchmark tests attempt to isolate the CPU and its supporting subsystem. One of the best known, CPUMark32 from Ziff-Davis Benchmark Operation of Morrisville, N.C., shows the 450-MHz AMD-K6-III outperforming the 500-MHz Pentium III by 12 percent.

But another Ziff-Davis benchmark, Winstone99, which measures performance in certain applications, has the same K6-III beating the same Pentium III by only 2 percent in home applications and losing by 2 percent in business applications.

It is best to choose application-specific benchmarks with your own needs in mind. Many of the benchmarks cited most often are meant to show off graphics power'a critical factor for games and graphics professionals, but not the best measure of plain-old office performance. Look for tests that employ office applications.

All three of the extant x86 chip vendors'Intel, AMD and Rise Technology'have significantly faster chips planned for release within a year.

Intel's first serious response to the new AMD Athlon is code-named Coppermine, a 600-MHz-plus Pentium III with the new 133-MHz bus. After that will be a faster notebook chip called the Mobile Pentium III, followed by Willamette, a so-called seventh-generation CPU regarded as a more direct Athlon competitor because of its much higher clock speeds and cache sizes.

Beyond that, the company plans a class of 64-bit chips codeveloped with Hewlett-Packard Co., called the IA-64, that are expected next year.

Chip futures

Meanwhile, Rise Technology plans to introduce a faster next-generation chip, the mP6 II, with an added Level 2 cache, even though the company hasn't had much success with its first one. And Cyrix's prospective new owner, VIA Technologies, reportedly will go ahead with Cyrix's existing plan for a new MII with a 256K Level 2 cache, followed by a totally new MII design in 2000.

IDT had talked about a WinChip upgrade, but recent corporate uncertainty makes the company's processor road map too speculative to be relied upon.''

Of all the Intel alternatives, AMD clearly is the only one with a credible story to tell government information technology buyers. The company makes competitively priced CPUs that are on par with Pentium IIIs, has a technologically superior high-end PC chip already shipping in volume to computer makers, and can offer a broad portfolio of mobile CPUs.

But with one unprofitable fiscal quarter after another, AMD may only be proving that even the best can't compete with Intel.'

Check out seven alternative processors that can deliver performance, cache rivaling Intel

clock speeds
in MHz
Level 2
Type of
Speed of
bus in MHz
in lots
of 1,000
Advanced Micro
Devices Inc.
Sunnyvale, Calif.
AMD-K7Pentium III
AMD-K6-IIIPentium III400
Pentium II
Yes3DNow66 or 100$51
Pentium II
Yes3DNow66 or less$119
Pentium II
Cyrix Corp.
Richardson, Texas
Pentium II
YesMMX66 or 75
Rise Technology Co.
Santa Clara, Calif.

David Essex writes about information technology from Antrim, N.H.


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