Intel Desktop Celeron (SEPP) processor

266 MHz
No L2 cache
Single Edge Processor package (slot 1)

Engineering sample
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Celeron 266 based on Covington core was the first processor from Celeron series. While this processor had poor performance due to lack of L2 cache, it was very popular because with its low price and very high overclockability the CPU had very good price/performance ratio. Many Celerons 266 could be easily overclocked to 400 MHz by changing bus frequency from 66 MHz to 100 MHz. Even if the microprocessor wasn't running stable at 400 MHz, it was still possible to run it at 333 MHz by changing bus frequency to 83 MHz.

300 MHz
No L2 cache
Single Edge Processor package (slot 1)
Covington core

Boxed processor
Front view

300 MHz
128 KB L2 cache
Single Edge Processor package (slot 1)

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The first microprocessor based on Mendocino core. This processor is marked as "300A/66", the suffix "A" is used to distinguish it from older Covington Celeron 300/66 CPU. New feature in this Celeron was integrated 128 KB L2 cache running at the processor speed. Addition of the L2 cache was the main reason why the performance of this CPU was much better than performance of older Covington Celerons. Like the older Celeron 266, the Celeron 300A was a very good overclocker. It was possible to run the CPU at 450 MHz by using 100 MHz bus speed.

333 MHz
128 KB L2 cache
Single Edge Processor package (slot 1)
Mendocino core

Front view
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366 MHz
128 KB L2 cache
Single Edge Processor package (slot 1)
Mendocino core

Engineering sample
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400 MHz
128 KB L2 cache
Single Edge Processor package (slot 1)
Mendocino core

Engineering sample
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433 MHz
128 KB L2 cache
Single Edge Processor package (slot 1)
Mendocino core

Engineering sample
Front view
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