Intel Celeron 400A (Slot-1)

by Anand Lal Shimpi on January 27, 1999 5:01 PM EST
Just months before the release of Intel's "revolutionary" step towards cost-effective microprocessors, the cacheless Celeron 266 received some of the most intense levels of media-bashing the company ever experienced. The reasoning behind the intense hatred towards Intel because of their motion to remove all cache from the cache-filled Pentium II design they so devilishly advocated just a year before was because of a trivial argument stating that the business application performance of the Celeron would be too poor to be considered a viable option. Intel's Low-Cost Wonder
Before ever seeing the likeness of Intel's first Celeron clocked at 266, most users were convinced that the "Celery" would be a huge flop in sales.

The general prejudice of the public towards Intel's Celeron almost guaranteed it to be a failure, and in terms of overall sales, the initial Celeron processors without any L2 cache were nothing but marketing failures. However everyone makes mistakes, including the microprocessor giant Intel, and quickly learning from their mistakes Intel took no longer than a few months to outfit their once cacheless Celeron with 128KB of L2 cache running at clock speed and re-release the "flop" as the Celeron A, the "A" being tacked on to the end of the name to signify a difference between the original and the newer Celerons, and in the eyes of the public, an illustration of a well deserved letter grade on behalf of Intel.

The overclocking population was taken by surprise when the cacheless Celeron 266, albeit clock-locked, could be taken up to 400MHz and beyond depending on the specific case. This was quickly denounced as a fluke related to the fact that the cacheless Celeron didn't have any clock speed limiting L2 cache on-board to prevent it from being overclocked, and for the time, this justification stuck; until Intel dropped another bombshell on the market, the, now famous, Celeron 300A. As mentioned before, outfitted with a full 128KB of L2 cache running at clock speed, the Celeron 300A shocked the community once again with its ability to hit 450MHz (in most cases) and definitely achievable without being limited by the L2 cache.

The success overclockers received with the Celeron 300A was tremendous, however in the big picture, the overclocking population represents, at most, 5% of the entire PC processor purchasing community, making the 300A's golden secret a hidden treasure to most. The justification for the 300A's overclocking success among those that did happen to uncover the treasure was Intel's extremely high processor yields (the "yield" is essentially the ratio of processors physically produced to those that work properly) in recent times. The question was raised as to whether or not Intel could simply remark the 300A as a 400MHz part and sell it a few months later without having to produce any new processors at all. In theory it was definitely possible since the 300A's were already making their way up to the 450MHz with relatively few problems, and those that did have problems usually only needed a quick bump up to a higher core voltage and they were on their way. Wouldn't it make sense for Intel to stay on the safe side and release a Celeron A processor at 400MHz rather than ramp up production on a higher yield Celeron A at 450MHz? It definitely does make sense, but before we start making any assumptions we'll want to take a few steps back and define the Celeron.

Taking a few steps back: Defining the Celeron

What makes a Celeron a Celeron? At first, as mentioned before, it was the processor’s obvious lack of L2 cache, however since its initial introduction things have changed considerably. How important is L2 cache to the day to day usage of your computer, can you really survive without it? The answer is yes.

Although you’ll always hear someone commenting on how their processor has more cache and is therefore better, the fact of the matter is that the 512KB of L2 cache present on the current generation of Pentium II processors and the upcoming Pentium III processors is more than enough to suit our needs. Why have it then? Because, from a marketing point of view, saying you have 512KB of L2 cache while the competition is playing around with less than < that number is a better investment, especially considering that adding the extra cache does not increase the overall cost to manufacture the processor by too extreme of a degree. At the same time, Intel had no idea how the market would react to the grand "more cache at a slower speed vs less cache at a faster speed debate," therefore, to stay on the safe side, the Pentium II was outfitted with a hefty amount of cache operating at a reasonable frequency.

What is the difference between 512KB of L2 cache running at = clock speed and 128KB of L2 cache running at clock speed? In terms of performance, very little. If a CPU attempts to access data located in the cache and fails during the request (a cache miss), regardless of how much L2 cache is present and how fast it is operating, the performance of the system (overall) will not vary as a direct result of the cache size/speed. The only time performance would be biased towards one of the two processors would be in the event that the CPU succeeds in retrieving the data (a cache hit), in which case the CPU with the faster cache would prevail. The thing to note is that, in spite of the faster operating frequency, the L2 cache in both cases affects performance virtually identically in that a 400MHz processor with 128KB of L2 cache running at clock speed would perform as a generally equal competitor to a 400MHz processor with 512KB of L2 cache running at 200MHz (1/2 clock speed). This "rule of thumb" applies in virtually all cases, except for server situations, where the basic rules of computing and performance do not necessarily apply, however for the sake of simplicity, servers will be eliminated from the comparison.

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  • microAmp - Sunday, August 27, 2006 - link

    Used this processor as my 1st build. Ahh, the memories. :)

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