Intel Celeron

By : http://en.wikipedia.org/


Celeron


Produced:April 1998
Manufacturer:Intel
CPU Speeds:266 MHz to 3.60 GHz
FSB Speeds:66 MHz to 200 MHz
Process:(MOSFET channel length)0.25 µm to 0.065 µm
Instruction Set:x86, x86-64
Microarchitecture:P6, NetBurst, Core
Sockets:
· Slot 1
· Socket 370
· Socket 478
· LGA 775
Cores:
· Covington
· Mendocino
· Coppermine-128
· Tualatin-256
· Willamette-128
· Northwood-128
· Prescott-256


Celeron


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) product lines (currently Core 2 Duo and formerly Pentium). Introduced in April 1998, the first Celeron was based on the Pentium II core. Later versions were based on the Pentium III, Pentium 4,Pentium M, and Core 2 Duo. 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.
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, AMD's K6, and IDT Winchip. Intel's existing low-end product, the Pentium MMX, was no longer performance competitive at 233MHz[3]. 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 (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. Covington was only manufactured in slot 1 SEPP format.
The Mendocino Celeron, launched August 24th, 1998, was the first mass-market CPU to utilise on-die L2 cache. Where as Covington had no secondary cache at all, Mendocino included 128 KiB of L2 cache running at full clock speed. The first Mendocino-core Celeron was clocked at a then-modest 300 MHz but offered almost twice the performance of the old cacheless Covington Celeron at the same clockspeed. To distinguish it from the older Covington 300 MHz, Intel called the Mendocino core Celeron 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 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. 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 rivaled the fastest x86 processors available.
At the time on-die cache was 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 operates at the same clock frequency as the CPU. All other CPUs at that time used motherboard 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 or 1 MiB), but they carried the performance penalty of slower cache speed, typically running at FSB speed (60 to 100 MHz) for motherboard mounted L2 cache. The implementation of the Pentium II's 512 KiB of L2 cache was unique at the time (and later copied by AMD's Athlon), being comprised of moderately high-speed L2 cache chips mounted on a special-purpose board alongside the processor itself, running at half processor speed and communicating with the CPU through a special backside bus. This method of cache placement was expensive and imposed practical cache-size limits, but allowed the Pentium II to be clocked faster and avoided front side bus RAM/L2 cache contention typical with motherboard-placed L2 cache configurations.
Over time, newer Mendocino processors were released at 333, 366, 400, 433, 466, 500, and 533 MHz. The "Mendocino" Celeron CPU came only designed for a 66 MHz frontside bus, but this would not be a serious performance bottleneck until clock speeds reached higher levels.
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 adapters (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, 600 MHz.
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.
The next generation Celeron was the Coppermine-128 (sometimes known as the "Celeron II"). These were a derivative of Intel's Coppermine Pentium III and were released on March 29th, 2000[12]. Like the Mendocino, the Celeron-128 used 128 KiB of on-chip L2 cache and was (initially) restricted to a 66 MHz bus speed, but the big news was the addition of SSE instructions, due to the new Coppermine core. Other than half the L2 cache (128 KiB instead of 256 KiB) and a slower FSB (66 to 100 MHz instead of 100 to 133 MHz), the Coppermine Celeron was identical to the Coppermine Pentium III.
All Coppermine-128s were produced in the same FCPGA Socket 370 format that most Coppermine Pentium III CPUs used. These Celeron processors began 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 were diminishing returns on performance as clock rate increased. On January 3, 2001, Intel switched to a 100 MHz bus with the launch of the 800 MHz Celeron, resulting in a significant performance-per-clock improvement[13]. All Celeron-128 CPUs from 800 MHz and faster use the 100 MHz front side bus. Various models were made at 800, 850, 900, 950, 1000, and 1100 MHz.
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
These Celeron processors, released initially at 1200 MHz (1.2 GHz) on October 2nd, 2001[14], were based on Pentium III Tualatin core and made with a 0.13 micrometer process for the FCPGA2 socket 370 . 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. Intel later released 1000 MHz 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)[15]. A 1300 MHz chip, launched January 4, 2002[16], and finally a 1400 MHz chip, launched May 15, 2002 (the same day as the Netburst Williamette 1.7 GHz Celeron launch)[17], marked the end of the Tualatin-256 line.
With regards to core functionality, Tualatin-256 was again quite similar to its Pentium III sibling. The most significant difference was the slower 100 MHz bus, it and had only 256 KiB of L2 cache (where as the Pentium III had either 256 KiB or 512 KiB of L2 cache). Furthermore, the Tualeron's L2 cache had a higher latency which boosted manufacturing yields for this budget CPU.
Despite offering much improved performance over the Coppermine Celeron it superceded, the Tualatin Celeron still suffered stiff competition from AMD's Duron budget processor[18]. Intel later responded by releasing the Netburst Williamette Celeron, and for some time Tualatin Celerons were manufactured and sold in parallel with their replacement Pentium 4-based Celerons.
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 (NetBurst)
Willamette-128
These Celerons were for socket 478 and were based on the Willamette Pentium 4 core, being a completely different design compared to the previous Tualatin Celeron. These are often known as the "Celeron 4". Their L2 cache (128 KiB) is half that of the Pentium 4 Williamette's 256 KiB of L2 cache, but otherwise the two are very similar. With the transition to the Pentium 4 core the Celeron now featured SSE2 instructions. The ability to share the same socket as the Pentium 4 meant that the Celeron now had the option to use RDRAM, DDR SDRAM, or traditional SDRAM. Williamette Celerons were launched May 15, 2002, initially at 1.7GHz, and offered a noticeable performance improvement over the older Tualatin Celeron 1300 MHz part, being able to finally best the Duron 1.3 GHz, which at the time was AMD's top competing budget processor. On June 12th, 2002, Intel launched the last Williamette Celeron, a 1.8GHz model.
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 socket 478 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. The Northwood-128 family of processors were initially released as a 2.0 GHz Model (a 1.9GHz model was announced earlier, but never launched) on September 18th, 2002. Since that time Intel has released at total of 10 different speed grades ranging from 1.8GHz to 2.8GHz, before being surpassed by the Celeron D. Although the Northwood Celerons suffer considerably from their small L2 cache, some speed grades have been favored in the enthusiast market, because like the old 300A, they can run well above their rated speeds.
In Intel's "Family/Model/Stepping" scheme, Northwood Celerons and Pentium 4s are family 15, model 2, and their Intel product code is 80532.