Celeron

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Celeron is a brand name given by Intel Corp. to a large number of different x86 microprocessor models that they produced and marketed as a budget/value CPU line. The Celeron family complements Intel's higher-performance (and more expensive) Pentium CPU family. Introduced in April 1998, the first Celeron was based on the Pentium II core. Later versions were based on the Pentium III, Pentium 4, and Pentium M. These processors are suitable for most applications, but their performance is somewhat limited when it comes to running intense applications, such as cutting edge games or graphical modeling programs, as compared to that of their high-end counterparts.

Background

As a product concept, the Celeron was introduced in response to Intel's loss of the low-end market, in particular to Cyrix's 6x86 and AMD's K6, but also to other competitors such as the IDT Winchip. Intel's existing low-end product, the Pentium MMX, was no longer performance competitive. Although a faster Pentium MMX would have been a lower-risk strategy, the industry standard Socket 7 platform hosted a market of competitor CPUs which could be drop-in replacements for the Pentium MMX. Instead, Intel pursued a budget part that was pin-compatible with their high-end Pentium II product, using the Pentium II's (Slot 1) interface. The Celeron was used in many low end machines and, in some ways, became the standard for non-gaming computers.

Celeron & Mobile Celeron (P6)

Covington

The first Celeron (codenamed Covington) was essentially a 266 MHz Deschutes Pentium II manufactured without any secondary cache at all. Covington also shared the 80523 product code of Deschutes. Although clocked at 266 or 300 MHz (Frequencies 33 to 66 MHz higher than the desktop version of the Pentium w/MMX), the cacheless Celerons were a good deal slower than the parts they were designed to replace. Substantial numbers were sold on first release, largely on the strength of the Intel name, but the Celeron quickly achieved a poor reputation both in the trade press and among computer professionals. The initial market interest faded rapidly in the face of its poor performance and with sales at a very low level, Intel felt obliged to develop a substantially faster replacement as soon as possible. Nevertheless the first Celerons were quite popular among some overclockers, for their flexible overclockability and reasonable price.

Mendocino

Intel was well aware of the poor reputation of the original Celeron and determined not to make the same mistake twice, with the result that the new Mendocino core Celeron was a good performer from the outset. Indeed, most industry analysts regarded the first Mendocino-based Celerons as too successful—performance was sufficiently high to not only compete strongly with rival parts, but also to attract buyers away from Intel's high-profit flagship, the Pentium II.

The key to the new Celeron's performance was cache. Where the old model had no secondary cache at all, the new part included 128 KiB of L2 cache as part of the chip itself. Otherwise, it was identical. With a total of 19.2 million transistors (including cache) on a single chip, the Mendocino Celeron was difficult and expensive to manufacture, but Intel managed a flawless execution of an ambitious project.

The first Mendocino-core Celeron was clocked at a then-modest 300 MHz but was almost twice as fast as the old cacheless Celeron at the same clockspeed. To distinguish it from the old model, Intel called it the 300A. Although the other Mendocino Celerons (the 333 MHz part, for example) did not have an A appended, some people call all Mendocino processors "Celeron-A" regardless of speed.

The Mendocino Celeron was the first mass-market CPU to utilise on-chip L2 cache. On-chip cache is difficult to manufacture; especially L2 as more of it is needed to attain an adequate level of performance. A benefit of on-die cache is that it can be made to run much faster than individual off-chip cache chips. Contrast this with the other common cache arrangements at that time. Most CPUs used mainboard mounted or slot mounted secondary L2 cache, which was very easy to manufacture, cheap, and simple to enlarge to any desired size. Typical cache sizes were 512 KiB to 1 MiB, typical speeds 66 to 100 MHz. The Pentium II had a pair of moderately high-speed L2 cache chips mounted on a special-purpose board alongside the processor itself. This was expensive and imposed practical cache-size limits, but allowed it to be clocked faster. Typical size was 512 KiB, always running at 1/2 of the processor speed. The new Mendocino Celeron had only 128 KiB of cache, but ran it at full clock speed.

Although the Mendocino Celeron cache was rather small, its high clock speed more than overcame that handicap, and the Mendocino Celeron was a success, particularly with the enthusiast market. Overclockers soon discovered that, given a high-end motherboard, the Celeron 300A could run reliably at 450 MHz. This was achieved by simply increasing the Front Side Bus (FSB) speed from the stock 66 MHz to the 100 MHz spec of the Pentium II. At this speed, the Mendocino Celeron rivalled the fastest x86 processors available.

However, this only came about due to Intel converting one of their manufacturing plants that was at the time producing Pentium II processors at 450 MHz to produce Celerons that ran at 300 MHz, in response to a new budget aimed processor from AMD, which despite returning a loss allowed Intel to regain their reputation in the lower cost market, making the Celeron 300A a crippled Pentium II rather than a proper Celeron.

Over time, newer Mendocino processors were released at 333, 366, 400, 433, 466, 500, and 533 MHz. They all ran on the 66 MHz FSB, which was not a particular issue with the 300, but became a major limitation with the faster-clocked parts, and Mendocino Celerons from about 433 MHz upwards were adequate rather than good.

The Mendocino Celerons also introduced new packaging. When the Mendocinos debuted they came in both a Slot 1 SEPP and Socket 370 PPGA package. The Slot 1 form had been designed to accommodate the off-chip cache of the Pentium II and had mounting problems with motherboards. Because all Celerons are a single-chip design, however, there was no reason to retain the slot packaging for L2 cache storage, and Intel discontinued the Slot 1 variant: beginning with the 466 MHz part, only the PPGA Socket 370 form was offered. (Third-party manufacturers made motherboard slot-to-socket adaptors (nicknamed Slotkets) available for a few dollars, which allowed, for example, a Celeron 500 to be fitted to a Slot 1 motherboard.) One interesting note about the PPGA Socket 370 Mendocinos is that SMP (symmetric multiprocessing) mode was available, and there was at least one motherboard released (the ABIT BP6) which took advantage of this fact.

The Mendocino also came in a mobile variant, with speeds from 266, 300, 333, 366, 400, 433, and 466, 500, 533, 566, 600MHz.

In Intel's "Family/Model/Stepping" scheme, Mendocino CPUs are family 6, model 6 and their Intel product code is 80524. These identifiers are shared with the related Dixon Mobile Pentium II variant.

Coppermine-128

The next generation Celeron was the Coppermine-128 (sometimes known as the "Celeron II"). These were a derivative of Intel's latest high-end part, the Coppermine Pentium III and were released in March 2000. Like the Mendocino, the Celeron-128 used 128 KiB of on-chip L2 cache and was restricted to a 66 MHz bus speed. It was identical to the Pentium III except for the smaller secondary cache and the much slower bus.

Although in theory the Celeron-128 had an updated core, the benefit of this was not noticeable. The Celeron was, by this time, the only mainstream CPU still using a 66 MHz bus and running 66 MHz RAM, and was significantly slower than any major competitor. Sales gradually dwindled as the industry moved on and, although making a 100 MHz bus version would have been a trivially easy task, Intel chose not to—probably because they had major production problems at that time and preferred to concentrate available resources on trying to ship sufficient volumes of the high-margin Pentium III.

All Coppermine-128s were produced in the same FCPGA Socket 370 format that most Coppermine Pentium IIIs used. These Celerons started at 533 MHz and continued through 566, 600, 633, 666, 700, 733, and 766 MHz. Because of the limitations of the 66 MHz bus, there was very little performance difference between the higher-clocked models; so long as the major competition was the elderly AMD K6-2, this was acceptable. In July 2000, however, AMD released their Athlon-derived Duron—a budget CPU with a faster bus and larger caches. The Celeron-128 became almost as uncompetitive as the original 266 MHz part had been.

However some benefit on performance could be gained through overclocking, by operating the Coppermine-128 CPUs with a 100 MHz FSB. Overclocking a 566 MHz Celeron to 850 MHz or a 600 MHz to 900 MHz gave the best results, since these systems usually proved stable without the requirement of additional cooling or overvolting. In particular a number of 600 MHz Celerons had been marketed which operated with a default core voltage of 1.7 V: when running on a 100 MHz FSB these processors proved to be even more stable if compared to previous batches of 600 MHz Celerons with core voltage of 1.5 V.

On January 3, 2001, Intel finally switched to a 100 MHz bus, and the performance improvement was startling. Although the Celeron 800 (the first of the 100 MHz bus parts) was still less powerful than the Duron, it was within a few percent and a perfectly viable option. All Celeron-128s from the 800 up used the 100 MHz Front Side Bus. Various models were made at 800, 850, 900, 950, 1000, and 1100 MHz.

The Coppermine-128 was used well into 2002. Early on it was popular in entry level desktops such as the eMachines eTower series. Often the processor would be permanently soldered onto the motherboard rather than being installed in a ZIF socket. Although always near the bottom of the performance table, it sometimes found a particular niche in low-power applications.

In Intel's "Family/Model/Stepping" scheme, Coppermine Celerons and Pentium IIIs are family 6, model 8 and their Intel product code is 80526.

Tualatin-256

The next series of Celeron processors was based on Pentium III Tualatin core, and made with a 0.13 micrometer process. They were nicknamed "Tualeron" — a portmanteau of the words Tualatin and Celeron. Some software and users refer to the chips as "Celeron-S", referring to the chip's lineage with the Pentium III-S, but this is not an official designation. The series began with 1000 and 1100 MHz parts (which were given the extension "A" to their name to differentiate them from the Coppermine-128 of the same speed they replaced) and the line continued with 1200, 1300, and 1400 MHz chips.

Tualerons were nearly identical to their Pentium III sibling. The most significant difference was that the Celeron used a 100 MHz bus rather than the 133 MHz bus of the Tualatin-core Pentium III processors. Further, the Tualeron's L2 had a latency of "1," where as the PIII's L2 cache had a latency of "0." Tualeron's were excellent overclockers, since they had higher multipliers and users could put them on a 133 MHz bus easily. The Celerons came with 256 KiB cache, while the Tualatin-core Pentium III processors came with either 256 KiB or 512 KiB cache.

The Tualatin-based Celeron was the last of the P6-core Celerons. For some time they were manufactured and sold in parallel with their replacement, the Pentium 4-based Celerons. Most users assumed that the newer parts, with their much higher clockspeeds, were significantly faster: they were not, and canny buyers snapped up the last of the P6 Tualatin Celerons, especially in notebook systems where the much lower power consumption translated into longer battery life.

In Intel's "Family/Model/Stepping" scheme, Tualatin Celerons and Pentium IIIs are family 6, model 11 and their Intel product code is 80530.

Celeron & Mobile Celeron (NetBurst)

Willamette-128

The next series of Celerons was based on the Willamette Pentium 4 core and were, in consequence, a completely different design. These are often known as the "Celeron 4". They have 128 KiB rather than 256 KiB or 512 KiB of L2 cache, but are otherwise very similar. Although the P4-based Celerons suffer considerably from their smaller caches, some speed grades have been favored in the enthusiast market, because like the old 300A, they can run well above their rated speeds. Some overclockers say that the Celeron is the best chip for overclocking because of its flexibility and lower heat production due to its smaller cache size.

In Intel's "Family/Model/Stepping" scheme, Willamette Celerons and Pentium 4s are family 15, model 1, and their Intel product code is 80531.

Northwood-128

These Celerons are based on the Northwood Pentium 4 core, and also have 128 KiB of L2 cache. The only difference between the Northwood-128 and the Willamette-128 Celeron is the fact that it was built on the new 0.13 micrometre process which shrunk the die size, increased the transistor count, and lowered the core voltage from 1.7 V on the Willamette-128 to 1.52 V for the Northwood-128. Despite these differences, they are functionally the same as the Willamette-128 Celeron, and perform largely the same clock-for-clock.

In Intel's "Family/Model/Stepping" scheme, Northwood Celerons and Pentium 4s are family 15, model 2, and their Intel product code is 80532.

Northwood-256

These are the Mobile Celeron range used in laptops. Also based on the Northwood core, they feature a 256 KiB L2 Cache.

Celeron M

Banias-512

This Celeron (sold under the Celeron M brand) is based on the Banias Pentium M, and differs from its parent in that it has half the L2 cache, and does not support the clock-varying SpeedStep technology. It performs reasonably well compared to the Pentium M, but battery life is noticeably shorter on a Celeron M–based notebook than it is on a comparable Pentium M notebook.

A system based on the Celeron M processor may not use the Centrino brand name, regardless of what chipset and Wi-Fi components are used.

In Intel's "Family/Model/Stepping" scheme, Banias Celeron Ms and Pentium Ms are family 6, model 9 and their Intel product code is 80535.

Shelton

The Shelton core is a Banias core without any L2 cache, and without SpeedStep. It is used in Intel's small form factor D845GVSH motherboard, intended for Asian and South American markets. The processor identifies itself as a "Intel Celeron 1.0B GHz", to differentiate it from the previous Coppermine-128 and "Tualeron" 1.0 GHz processors.

Dothan-1024

A 90 nm Celeron M with half of the L2 cache of the 90 nm Dothan Pentium Ms (twice the L2 cache of the 130nm Celeron Ms, though), and, like its predecessor, lacking SpeedStep.

In Intel's "Family/Model/Stepping" scheme, Dothan Celeron Ms and Pentium Ms are family 6, model 13 and their Intel product code is 80536.

Yonah-1024

The Celeron M 400-series is a 65 nm Celeron M based on the single-core Yonah Core Solo CPU. Like its predecessors in the Celeron M series, this Celeron M has half of the L2 cache (1 MiB) of Core Solo and lacks SpeedStep. This core also brings new features to Celeron M including a faster front side bus (533 MT/s), SSE3 instructions, and support for the XD bit.

Celeron D

Prescott-256

The first Celeron D processor is based on the Prescott Pentium 4 core and has a larger (than the previous NetBurst Celerons) 256 KiB cache. It also features a 533 MT/s bus and SSE3, and a 3xx model number (compared to 5xx for Pentium 4s and 7xx for Pentium Ms); specifically, they have been released thus far bearing model numbers of 355 (3.33 GHz), 350 (3.2 GHz), 345 (3.06 GHz) 340 (2.93 GHz), 335 (2.80 GHz), 330 (2.66 GHz), 325 (2.53 GHz), 320 (2.40 GHz), 315 (2.26 GHz), and 310 (2.13 GHz). They also have hardware-level support of Intel's EM64T technology by virtue of it also being built into the Prescott core, although the feature is disabled in all 3x0/3x5 models (with the exception of the Celeron D 355). It has been activated in all 3x1/3x6 models. The Intel Celeron D processor works with the Intel 845 and 865 chipset families. It should be noted that the "D" suffix actually stands for nothing. This name was assigned by Intel in order to differentiate this generation of Celeron from its predecessors.^[1] It should also be stated that unlike the Pentium D, the Celeron D is not a dual core processor.

In mid-2005, Intel refreshed the Celeron D with EM64T and XD Bit (eXecute Disable) enabled. Model numbers increase by 1 over the previous generation (e.g. 330 became 331), and were only manufactured for LGA 775.

In Intel's "Family/Model/Stepping" scheme, Prescott Celeron Ds and Pentium 4s are family 15, model 3 (up to stepping E0) or 4 (stepping E0 onwards), and their Intel product code is 80546 or 80547, depending on socket type.

Cedar Mill-512

Based on the Cedar Mill Pentium 4 core, this version of the Celeron D continues the 3xx naming scheme with the Celeron D 347 (3.06 GHz), 352 (3.2 GHz), 356 (3.33 GHz), and 360 (3.46 GHz) and retains the Prescott-V's feature set, except with double the L2 cache (512KB) and based on a 65nm manufacturing process.

In Intel's "Family/Model/Stepping" scheme, Cedar Mill Celeron Ds and Pentium 4s are family 15, model 6, and their Intel product code is 80552.

Future Celerons

Main article: Intel Core microarchitecture

Intel's roadmap lists a series of upcoming Celerons, based on the Intel Core microarchitecture. There is little current information about them, except that they will use the Conroe-L core,^[2] and will use a 400 model number sequence. They will be single-core processors for the value segment of the market, much like the AMD K8-based Sempron.

See also

• List of Intel Celeron microprocessors

References

External links

• Budget CPU Shootout - Popular hardware review website Anandtech compares Celerons to other similarly priced CPUs
• Intel Pentium II Celeron Covington and Mendocino specifications
• Intel Pentium III Celeron Coppermine and Tualatin specifications
• Intel Pentium4 Celeron Willamette, Northwood and Prescott specifications
• Intel's Celeron M homepage
• Intel Celeron M Banias, Dothan, and Yonah specifications
• Intel Pentium II and Pentium III based Celerons at cpu-collection.de