alt Hacker News>Celeron CPUs were usually CPUs that shared the same core architecture as the current Pentium standard, but often had a lower core clock speed, lower core memory speed, and/or had smaller L2 caches.
This had an interesting side effect: Celerons of that era overclocked extremely well (stable 300 -> 500MHz+), due to the smaller and simpler on-die L2 cache relative to the Pentiums of the era, whose L2 cache was much larger but had to be off-die (and less amenable to overclocking) as a result.
An overclocked dual Celeron could easily outperform the highest-end Pentiums of the era on clock-sensitive, cache-insensitive applications, especially those designed to take advantage of parallelism.
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Yeah; mine ran very stable at 466 for >decade. It was impressive.
You could attempt to head toward ~700 but I never could keep it stable there.
That was a bit of a two edged sword as the heavily overclocked Celerons would benchmark extremely well, but be somewhat disappointing in actual applications due to the lack of cache space. It was right at the start of the era where cache misses became the defining factor in real world performance. CPUs ran ahead of DRAM and it has never caught back up, even as per-core CPU performance plateaued.
IIRC Celeron cache being on die was actually faster as it was on die, this was mitigated on the Pentiums by there being more of it. It seemed like in games the faster cache performed better.
Another thing that helped the Celeron overclocking craze is Intel seemed to damage the brand badly out of the gate. The original Celerons had no cache at all, performed terribly and took a beating in PC reviews. So even though the A variants were much better this still had a stink on them.
The thing that probably helped the Celeron the most with overclocking though was they gimped them by only giving them a 66mhz front side bus speed. Since you had to increase this number to push the locked multiplier CPU speed up this was an advantage if you were going to overclock as you could buy a capable motherboard and run it at stable 100mhz. Whereas you'd have a lot more system wide problems trying to push a Pentium's 100mhz bus higher.