Celeron

The Celeron brand refers to a range of Intel's x86 CPUs for budget/value personal computers. Considered Intel's "economic" processor, the Celeron branded processors have complemented Intel's higher-performance (and more expensive) brands. Intel has given the brand the motto, "delivering great quality at an exceptional value." Celeron processors can run all IA-32 computer programs, but their performance is somewhat lower when compared to similar, but higher priced, Intel CPU brands. For example, the Celeron brand will often have less cache memory, or have advanced features purposely disabled. These missing features have had a variable impact on performance. In some cases, the effect was significant and in other cases the differences were relatively minor. Many of the Celeron designs have achieved a very high "bang to the buck," while at other times, the performance difference has been noticable. For example, some intense application software, such as cutting edge PC games, programs for video compression, video editing, or solid modeling (CAD, engineering analysis, computer graphics and animation, rapid prototyping, medical testing, product visualization, and visualization of scientific research), etc. may not perform as well on the Celeron family. This has been the primary justification for the higher cost of other Intel CPU brands vs. the Celeron.Introduced in April 1998, the first Celeron branded CPU was based on the Pentium II branded core. Subsequent Celeron branded CPUs were based on the Pentium III, Pentium 4, Pentium M, and Core 2 Duo branded processors. The latest Celeron design (as of January 2008) is based on the Core 2 Duo (Allendale). This design features independent processing cores (CPUs), but with only half as much cache memory as the comparable Core 2 Duo offering.

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, AMD's K6, and IDT Winchip. Intel's existing low-end product, the Pentium MMX, was no longer performance competitive at 233 MHz. 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)

The Mendocino Celeron, launched 24 August 1998, was the first mass-market CPU to use on-die L2 cache. Whereas 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 clock speed. 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.

Coppermine-128

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 29, 2000. 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. 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.

Celeron D

Prescott-256 Celeron D processors, initially launched June 25, 2004,[20] feature double the L1 cache (16 KiB) and L2 cache (256 KiB) as compared to the previous Willamette and Northwood desktop Celerons, by virtue of being based on the Prescott Pentium 4 core. 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). The Prescott-256 Celeron D was manufactured for socket 478 as well LGA 775, and they were released carrying 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 Intel 64 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 model 355). It has been activated in all 3x1 and 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 has no official designation. It is used simply to distinguish this line of Celeron from the previous, lower performing Northwood and Willamette series, and also from the mobile series, the Celeron M. It should also be stated that unlike the Pentium D, the Celeron D is not a dual core processor.The Celeron D was a major performance improvement over previous Netburst Celerons. A test using a variety of applications, run by Derek Wilson at Anandtech.com, showed that the new Celeron D architecture alone offered up performance improvements on average of >10% over a Northwood Celeron when both CPUs were run at the same bus and clock speed. The addition of SSE 3 instructions and the higher FSB only added to this already impressive gain.Despite its many improvements, the Prescott core of the Celeron D had at least one major drawback: heat. Unlike the fairly cool running Northwood Celeron, the Prescott-256 had a class-rated TDP of 73 watts, which prompted Intel to include a more intricate copper core/aluminum finned cooler to help handle the additional heat.In mid-2005, Intel refreshed the Celeron D with Intel 64 and XD Bit (eXecute Disable) enabled. Model numbers increase by 1 over the previous generation (e.g. 330 became 331). This only applied to LGA 775 Celeron Ds. There is no Socket 478 CPU with 64-bit or XD Bit capabilities.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.