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Microprocessor Technology 2000
by By Herbert Wong, Jr., NOCCC Hardware SIG Leader, ocug@SingularityTechnology.com - May 19, 2000 at 17:50:28:
The two giants of the PC microprocessor market, Intel and Advanced Micro Devices (AMD), have escalated their rivalry with a new generation of…the same old thing. The speeds are up and there are a few new bells and whistles, but nothing revolutionary has been added to this round.Intel strives to make changes to the aging PC architecture that was introduced with the Pentium generation microprocessor. The Pentium’s system bus was either 60 or 66 megahertz. The Pentium II initially used 66 megahertz and later increased this to 100 megahertz. The Pentium III supports either 100 or 133 megahertz; plus changes to support RDRAM (Rambus dynamic random access memory). AMD’s Athlon microprocessor supports a system bus of up to 200-megahertz.
The most significant improvement is SIMD (single instruction, multiple data) instructions that provide basic parallel processing for some floating-point instructions. Both AMD and Intel have their own proprietary technology. Multimedia applications could benefit the most from this addition.
Feature Descriptions—
The Floating-Point Unit (FPU) supports IEEE standard 754 (32-bit and 64-bit formats) and an 80-bit format. The FPU originally was an optional chip that had its own socket. The FPU has been integrated with the CPU (central processing unit) since the Intel 80486 microprocessors.
Intel’s MMX extensions provide 54 instructions, eight 64-bit wide MMX registers, and four new data types. These integer instructions share the floating-point unit’s registers.
Intel’s Streaming SIMD (single instruction multiple data) extensions provide seventy additional instructions (single instruction, multiple-data-floating point, additional SIMD-integer, and cacheability-control instructions) most of which, according to Intel, are supposed to improve performance in advanced imaging, 3D, streaming audio and video, and speech recognition applications.
AMD’s 3DNow! technology has 45 instructions. Nineteen new instructions improve AMD’s version of MMX integer operations and five new instructions are for DSP (digital signal processing). AMD’s 3DNow! technology is an alternative to Intel’s Streaming SIMD extensions.
The Microprocessors—
Intel Celeron microprocessors are currently available in speeds of 466, 500, 533, 533A, 566, and 600 megahertz (and others). The level-1 cache is 32 kilobytes (16 kilobytes each for instructions and data). There is an integrated level-2 cache of 128 kilobytes that runs at full processor speed. The front side bus is currently 66 megahertz. The latest Coppermine (0.18 micron fabrication process and Streaming SIMD extensions) versions (currently 533A, 566, and 600 megahertz) include Intel’s Streaming SIMD extensions.
Current Celerons come in socket-370 compatible PPGA (plastic pin grid array for 466, 500, and 533 megahertz versions) and FC-PGA (Flip-Chip Pin Grid Array for 566 and 600 megahertz versions).
Intel Pentium II microprocessors, introduced in May 1997, are available in speeds of 233, 266, 300, 333, 350, 400, and 450 megahertz. The earliest Pentium IIs had a 66-megahertz front side bus. The 350, 400, and 450-megahertz versions have a 100 megahertz front side bus.
Intel Pentium III microprocessors are available in speeds of 450, 500, 550, 600, 650, 667, 700, 733, 750, 800, 850, 866, and 1,000 megahertz (and others). There are 32 kilobytes of non-blocking level-1 cache (16 kilobytes each for data and instructions) and 512 kilobytes of level-2 cache. Early versions of the level-2 cache transferred data to the microprocessor at one-half the processor’s core frequency. The latest Coppermine (0.18 micron fabrication process and Streaming SIMD extensions) versions have level-2 cache that runs at the same speed as the processor’s core frequency. This should add a fair improvement in performance without a change in actual microprocessor frequency.
The Pentium III front side bus can be either 100 megahertz or 133 megahertz (models with a “B” suffix) depending upon the version of microprocessor purchased. You’ll have to pick a version before you build your system so you can purchase suitable (100 or 133 megahertz) SD-RAM or Rambus DRAM.
The Pentium III is now available in three versions, socket-370, slot-1, and slot-2 (for Xeon versions). Socket-370 versions have an “E” suffix.
There is a new and “optional” unique Processor Serial Number embedded in each PIII. Those who are concerned about personal privacy should consider turning off this “feature.”
Advanced Micro Devices K6-2 and K6-III microprocessors are comparable to Intel Pentium and Pentium II microprocessors. They can still be found in mobile forms (for notebooks, laptops, etc.), but are generally discontinued in the normal desktop format.
Advanced Micro Devices introduced its flagship Athlon brand (also known as K7, as in seventh generation) last year. It is designed to compete directly at any give frequency (megahertz) with the corresponding Intel Pentium III microprocessor.
Advanced Micro Devices (AMD) Athlon microprocessors are currently available in speeds of 600, 650, 700, 750, 800, 850, 900, 950, and 1,000 megahertz. The Athlon has a level-1 cache of 128 kilobytes and a level-2 cache of 512 kilobytes to 8 megabytes with a 64-bit wide controller. There is support for MMX and 3DNow!.
Sockets—
There are now six different ways of connecting a microprocessor to its motherboard (also known as a mainboard). They are Super7, slot-1, slot-2, socket-370, slot-A, and wave-soldering (or some other permanent mounting).
Sockets look like little platforms that are mounted flat on the motherboard’s surface. Row after concentric row of holes run around the top of the socket. The center of the socket is not needed, so it is usually removed, giving it the appearance of a rectangle with a rectangle removed from the middle. A lever (that runs along one side of the socket) actuates a spring that clamps the microprocessor’s pins (that easily go through the holes) when it is inserted into the socket. Thus the name zero insertion force (ZIF) socket.
Processors that go in sockets are ball grid array (BGA), plastic pin grid array (PPGA), or Flip-Chip Pin Grid Array (FC-PGA) packages. The Flip-Chip PGA design mounts the chip on the upper side of the microprocessor where it is easier to more intimately attach a heat-sink for improve cooling.
The trademarked Super7 is almost (or should be extinct). It is a ZIF-socket. It was created to extend the life of the Pentium and AMD K6-2 microprocessors. Motherboards for these microprocessors typically employ ALI Aladdin V and VIA Apollo MVP3 chipsets.
Slots—
Slots are relatively new to mainstream IBM PC microprocessors. The microprocessor’s circuitry is mounted on a pc-board (printed circuit board) that is inserted into the motherboard’s slot. Unlike PCI and ISA cards, these boards make electrical contact on a single edge, giving rise to the name SECC (single edge contact cartridge).
Slot-1 technology was created by Intel (for Pentium II, Pentium III, and Celeron microprocessors) because they claimed that there were technical reasons that prevented socket based microprocessors from reaching much higher frequencies. Closer to the truth was that Intel was able to charge licensing fees for the socket technology and force competing chipset makers to revamp their technologies.
The ultimate reason for slot-1 technology was to make bigger packages for the extra silicon that the external memory cache required when mated with the new CPU (central procession unit) itself. The proof for this is that the latest Pentium IIIs are now manufactured in BGA sockets that far exceed the frequencies of the slot-1 Pentium II designs. This reversal is due to improvements in fabrication process technology (Coppermine 0.18 micron) that shrinks the microprocessor and cache to a size that allows the socket format, again.
Slot-1 motherboards use Intel 440BX, Intel 440GX, Intel 810e, Intel 820, Intel 840, VIA Apollo Pro 133A, etc. chipsets. Slot-1 has 242-contacts.
Some motherboards have both a slot-1 and a socket-370 on them. You can now use one of either type of microprocessor on one of these boards. You’ll have to use another type of motherboard to enable dual processors.
Slot-2 motherboards use Intel 840, Intel 440GX, and Reliance HE chipsets. Only the Intel Xeon microprocessors use slot-2. The Xeons have large caches (1 or 2 megabytes) and are designed for use in servers.
Slot-A is used by AMD Athlon microprocessors. It is derived from workstations (DEC Alphas). The front side system bus can run at 200 megahertz. Slot-A motherboards use VIA Apollo KX133, AMD-750, and AMD-751/VIA686A chipsets.
AMD Recommendations—
The best way to achieve happiness when building a computer system based upon an AMD Athlon microprocessor is to do your research before making a purchase. It would appear that Athlon systems require components (motherboard, RAM, power supply, heat sink, etc.) that are more robust or compliant to specifications.
To this end, the AMD Athlon Processor System Configuration Recommendations (http://www1.amd.com/athlon/config) and Buyer’s Guide (http://www.amd.com/products/cpg/bguide.html) are the places to start. Also, visit the many other Computer Hardware Technology related links on the NOCCC Links page (http://www.noccc.org/links/index.html).
General Recommendations—
Microprocessors are comfortably fast, today. The least expensive currently available microprocessor in a suitable system (at least 128 megabytes of RAM, appropriate video accelerator, etc.) will run most business applications (word-processing, spreadsheets, e-mail, Web-browsing, etc.) quite adequately. The “sweet spot” is generally in the $100 to $200 price range.
The most demanding applications are 3D games (and video editing, photo editing, etc.). A system designed to play games must first have the best 3D video accelerator and then the best microprocessor that can be budgeted.
The feature improvements to look for when comparing different microprocessors are: front side system bus speed increase (from 66 to 100 to 133 to 200 megahertz), multimedia extensions (like 3DNow! and Streaming SIMD), CPU to level-2 cache speed (one-half microprocessor speed to full microprocessor speed), and, finally, microprocessor core speed (up to 1,000 megahertz or faster).
This article first appeared in the North Orange County Computer Club’s Orange Bytes newsletter (http://www.noccc.org/) for June 2000. You can find the latest version at http://www.SingularityTechnology.com/articles/cputech2000.html/. You can contact me at my new e-mail address (ocug@SingularityTechnology.com).
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