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7th September 2008, 08:09 PM
The Pentium III brand refers to Intel's 32-bit x86 desktop and mobile microprocessors (with the sixth-generation Intel P6 microarchitecture) introduced on February 26, 1999 and containing 9.5 million transistors. The brand's initial processors were very similar to the earlier CPUs branded Pentium II. The most notable difference was the addition of the SSE instruction set (to accelerate media processing and 3D graphics), and the introduction of a controversial serial number embedded in the chip during the manufacturing process.

Similarly to the Pentium II it superseded, the Pentium III was also accompanied by the Celeron brand for lower-end CPU versions, and the Xeon for high-end (server and workstation) derivatives. The Pentium III was eventually superseded by the Pentium 4, but its Tualatin core also served as the basis for the Pentium M CPUs, which used many ideas from the Intel P6 microarchitecture. Subsequently, it was the P-M microarchitecture of Pentium M branded CPUs, and not the NetBurst found in Pentium 4 processors, that formed the basis for Intel's energy-efficient Intel Core microarchitecture of CPUs branded Core 2, Pentium Dual-Core, Celeron (Core), and Xeon.


Pentium III cores
http://upload.wikimedia.org/wikipedia/en/thumb/9/97/Intel_P3Slot.jpg/180px-Intel_P3Slot.jpg

The original version, Katmai (Intel product code 80525), was very similar to the Pentium II (using a 0.25 µm fabrication process), the only differences being the introduction of SSE, and an improved L1 cache controller (which was the cause of the minor performance improvements over the latter PIIs). It was first released at speeds of 450 and 500 MHz. Two more versions were released: 550 MHz on May 17, 1999 and 600 MHz on August 2, 1999. On September 27, 1999 Intel released the 533B and 600B running with 533/600 MHz but using a 133 MHz FSB, all others use a 100 MHz FSB.

The Katmai used the same slot based design as the Pentium II but with the newer SECC2 cartridge that allowed direct CPU core contact with the heatsink. There've been some early models of the Pentium III with 450 and 500 MHZ with SECC cartridge being delivered for OEM-use only.

A notable stepping for enthusiasts was SL35D. This version of Katmai was officially rated for 450 MHz, but often contained cache chips for the 600 MHz model and thus usually was capable of running at 600 MHz.

Coppermine

http://upload.wikimedia.org/wikipedia/en/thumb/d/d4/PentiumIII_SECC2_Heatsink_Removed.jpg/180px-PentiumIII_SECC2_Heatsink_Removed.jpg

The second version, Coppermine, or 80526, had an integrated full-speed 256-bit 256 KiB L2 cache with lower latency, named Advanced Transfer Cache by Intel, which improved performance significantly over Katmai. Under competitive pressure from AMD’s Athlon processor, Intel also re-worked the chip internally, and finally fixed the well known instruction pipeline stalls. The result was a remarkable 30% increased performance in some applications where these stalls happened.

It was built on a 0.18 μm process. Pentium III Coppermines running at 500, 533, 550, 600, 650, 667, 700, and 733 MHz were first released on October 25, 1999. From December 1999 to May 2000, Intel released Pentium IIIs running at speeds of 750, 800, 850, 866, 900, 933 and 1000 MHz (1 GHz). Both 100 MHz FSB and 133 MHz FSB models were made.

A 1.13 GHz version was released in mid-2000 but famously recalled after a collaboration between HardOCP and Tom's Hardware discovered various instabilities with the operation of the new CPU speed grade. The Coppermine core was unable to reliably reach the 1.13 GHz speed without various tweaks to the processor's microcode, aggressive cooling, additional voltage (1.75 V vs. 1.65 V), and specifically validated platforms.[1] Intel only officially supported the processor on its own VC820 i820-based motherboard, but even this motherboard displayed instability in the independent tests of the hardware review sites. In benchmarks that were stable, performance was shown to be sub-par, with the 1.13 GHz CPU equalling a 1.0 GHz model. Tom's Hardware attributed this performance deficit to relaxed tuning of the CPU and motherboard to improve stability.[2] Intel needed at least six months to resolve the problems and re-released 1.1 GHz and 1.13 GHz versions in 2001.

A common misconception is that a modified version of the Coppermine was developed for Microsoft's Xbox game console. The Xbox does not actually use a Pentium III processor per se. It technically runs a Mobile Celeron 733 (Coppermine-128) in a Micro-PGA2 package. Given the fact that the Mobile Celeron 733 has the same 8-way associative cache used in Pentium III chips, it isn't a stretch to just call the Xbox CPU a "Pentium III with half the cache." Still, that statement isn't entirely correct.

Although the codename Coppermine makes it sound as if the chip was fabricated with copper interconnects, Coppermine in fact used aluminum interconnects.

Later in Coppermine's life, Intel implemented a heatspreader to improve contact between the CPU and the heatsink. The heatspreader itself didn't improve thermal conductivity, since it added another layer of metal and thermal paste between the CPU and the heatsink. But it greatly assisted in holding the heatsink flat against the CPU. Earlier Coppermine CPUs with bare cores made for challenging heatsink mounting.[3] If the heatsink was not flat against the core, heat transfer efficiency was crippled. Some heatsink makers also began using pads on their coolers, similar to what AMD did with the "Thunderbird" Athlon. The enthusiast community went so far as to create shims to assist in maintaining a flat interface.[4]

Coppermine-T

This core was supposed to be an intermediate step between Coppermine and Tualatin, with support for lower-voltage system logic present on the latter but core power within previously defined voltage specs of the former so it could work in older system boards. It existed in Intel's processor roadmap in 2000 but was cancelled on the way to production.

Intel did issue S-Spec production codes (e.g. SL5QK) for some late-model Coppermines that would work with low voltage system bus operation (GTL) at 1.25 V AGTL as well as normal 1.5 V AGTL+ signal levels, and would auto detect differential or single-ended clocking. These processors were probably intended for dual-processor motherboards. However core voltage was the same as other Coppermines.

Note: Some sources identified Coppermine cD0-stepping to be Coppermine-T. This is incorrect because cD0-stepping was merely a revision to the original Coppermine rather than a new core by itself. Intel was unlikely to have it placed in the roadmap as a new core codename. Stepping (version numbers) of processors could be compared to minor versions of software

Tualatin

The third version, Tualatin (80530), was really just a trial for Intel's new 0.13 µm process. As the Pentium 4 had a much bigger die size than the Pentium III, Intel would get more usable Pentium IIIs out of a wafer, and this would allow them to introduce the 0.13 µm Pentium 4 (Northwood) once the process was achieving optimal yields. Tualatin performed quite well, especially in variations which had 512 KiB L2 cache (called the Pentium III-S). The Pentium III-S variant was mainly intended for servers, especially those where power consumption mattered, i.e., thin blade servers.

Pentium III Tualatins were released during 2001 until early 2002 at speeds of 1.0, 1.13, 1.2, 1.26, 1.33 and 1.4 GHz. Overclockers discovered that 1.7-1.8 GHz was about the maximum frequency the Tualatin could achieve using air cooling.

Tualatins can usually be visually distinguished from Coppermine-based Pentium IIIs by the metal integrated heatspreader (IHS) fixed on top of the package. However the very last models of Coppermine Pentium IIIs also featured the IHS - the heatspreader is what distinguishes the FC-PGA2 package from the FC-PGA - both are for Socket 370 motherboards.[5] Because the IHS slightly reduces heat transfer efficiency, some overclockers would remove it to allow direct core-to-heatsink contact. This was even more dangerous with the smaller 130 nm core than it had been with the 180 nm Coppermine, with a risk of cracking or chipping the core, and the difficulty in making good flat contact between the top of the core and the heatsink. However, it did potentially improve cooling which could allow higher overclocking results. [6] Like with Coppermine, as a measure of protection several companies manufactured aftermarket shims to aid in flat heatsink mounting.

The Tualatin core was named after the Tualatin Valley and Tualatin River in Oregon, where Intel has large manufacturing and design facilities.

Pentium III's SSE implementation

http://upload.wikimedia.org/wikipedia/commons/thumb/2/28/Pentium_III_on_motherboard.jpg/180px-Pentium_III_on_motherboard.jpg

Since Katmai was built in the same 0.25 µm process as Pentium II "Deschutes", it had to implement SSE using as little silicon as possible. To achieve this goal, Intel implemented the 128-bit architecture by double-cycling the existing 64-bit data paths and by merging the SIMD-FP multiplier unit with the x87 scalar FPU multiplier into a single unit. To utilize the existing 64-bit data paths, Katmai issues each SIMD-FP instruction as two μops. To compensate partially for implementing only half of SSE’s architectural width, Katmai implements the SIMD-FP adder as a separate unit on the second dispatch port. This organization allows one half of a SIMD multiply and one half of an independent SIMD add to be issued together bringing the peak throughput back to four floating point operations per cycle — at least for code with an even distribution of multiplies and adds.[7]

The issue was that Katmai’s hardware-implementation contradicted the parallelism model implied by the SSE instruction-set. Programmers faced a code-scheduling dilemma: Should the SSE-code be tuned for Katmai's limited execution resources, or should it be tuned for a future processor with more resources? Katmai-specific SSE optimizations yielded the best possible performance from the Pentium III family, but was suboptimal for later Intel processors, such as the Pentium 4 and Core.

Core specifications

Katmai (0.25 µm)
L1-Cache: 16 + 16 KiB (Data + Instructions)
L2-Cache: 512 KiB, external chips on CPU module at 50% of CPU-speed
MMX, SSE
Slot 1 (SECC, SECC2)
Front side bus: 100, 133 MHz
VCore: 2.0 V, (600 MHz: 2.05 V)
First release: May 17, 1999
Clockrate: 450-600 MHz
100 MHz FSB: 450, 500, 550, 600 MHz
133 MHz FSB: 533, 600 MHz (B-models)

[edit] Coppermine (0.18 µm)
L1-Cache: 16 + 16 KiB (Data + Instructions)
L2-Cache: 256 KiB, fullspeed
MMX, SSE
Slot 1 (SECC2), Socket 370 (FC-PGA)
Front side bus: 100, 133 MHz
VCore: 1.6V, 1.65V, 1.70V, 1.76V (cD0, see below)
First release: October 25, 1999
Clockrate: 500 - 1133 MHz
100 MHz FSB: 500, 550, 600, 650, 700, 750, 800, 850, 900, 1000, 1100 MHz (E-Models)
133 MHz FSB: 533, 600, 667, 733, 800, 866, 933, 1000, 1133 MHz (EB-Models)

[edit] Coppermine cD0-stepping or Coppermine-T (0.18 µm)
L1-Cache: 16 + 16 KiB (Data + Instructions)
L2-Cache: 256 KiB, fullspeed
MMX, SSE
Socket 370 (FC-PGA, FC-PGA2)
Front side bus: 100 and 133 MHz
VCore: 1.75 V
First release: June 2001
Clockrate: 600 - 1133 MHz
100 MHz FSB: 600, 700, 750, 800, 850, 900, 1000, 1100 MHz
133 MHz FSB: 733, 800, 866, 933, 1000, 1133 MHz

[edit] Tualatin (0.13 µm)
L1-Cache: 16 + 16 KiB (Data + Instructions)
L2-Cache: 256 or 512 KiB, fullspeed
MMX, SSE, Hardware prefetch
Socket 370 (FC-PGA2)
Front side bus: 133 MHz
VCore: 1.45, 1.475 V
First release: 2001
Clockrate: 1000 - 1400 MHz
Pentium III (256 KiB L2-Cache): 1000, 1133, 1200, 1333, 1400 MHz
Pentium III-S (512 KiB L2-Cache): 1133, 1266, 1400 MHz

Controversy about privacy issues
The Pentium III was the first CPU to include an unique, retrievable, identification number, called PSN (Personal Serial Number).

On November 29, 1999, the Science and Technology Options Assessment Panel (STOA) of the European Parliament, following their report on electronic surveillance techniques asked parliamentary committee members to consider legal measures that would "prevent these chips from being installed in the computers of European citizens."[8]

Eventually Intel decided to make possible to disable the PSN.

References

1.^ Pabst, Thomas. Intel Admits Problems With Pentium III 1.13 GHz: Production and Shipments Halted, Tom's Hardware, August 28, 2000.
2.^ Pabst, Thomas. Latest Update On Intel's 1.13 GHz Pentium III, Tom's Hardware, August 28, 2000.
3.^ Alpha FC-PAL35T & POP66T Cooler Review, The Tech Zone, April 12, 2000.
4.^ Verbist, Tim. Copper Shims, Overclockers Online, December 3, 2000.
5.^ Lal Shimpi, Anand. Intel Pentium III 1.2 GHz 0.13-micron Tualatin: The Celeron of the Future, Anandtech, July 30, 2001.
6.^ Removing Your Integrated Heat Spreader, The Lunchbox, October 8, 2002.
7.^ Diefendorff Keith (March 8, 1999). "Pentium III = Pentium II + SSE: Internet SSE Architecture Boosts Multimedia Performance". Microprocessor Report. Volume 13, Number 3.
8.^ Advisory group asks EU to consider Pentium III ban, CNN, November 29, 1999.

External links

Listing of various PII, PIII, and Celeron alphanumeric model designations
Intel Pentium III technical specifications Nice overview, but use with caution: Some information on this site is in conflict with Intel's documentation.
Comparison of 7th generation x86 CPU architectures
Intel FAQ about the pentium III processor serial number

http://alladin.persiangig.com/image/image_new/wiki.JPG

منبع: http://en.wikipedia.org (http://en.wikipedia.org/)

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