Retro overclocking: World Records with legendary Celeron 300A

10.03.2015 01:13 |


English summary:

Finnish hardware site Muropaketti.com was established in 1999 and our first article was about overclocking Intel’s Celeron 300A processor to compete with the more expensive Pentium II.

In the past few years we managed to get suitable components (Abit BE6-2 motherboard & Mushkin 128 MB High Performance Rev 3.0 SDRAM) into our hands and after years of careful planning we started to hunt World Records with our Slot 1 Celeron 300A (SL32A).

First we optimized operating system (Win XP Lite) with proper tweaks for the best possible clock-to-clock efficiency, tested how high front side bus (FSB) we could reach with Coppermine Pentium III 600 (100) processor (175 MHz) and tested how high could Mushkin SDRAM run with CAS 2-2-2 memory settings (159 MHz, 3,6v). During the preparations we already managed to break some World Records with Coppermine Pentium III 600 (100).

To start the Celeron 300A tests with dry ice (-79 degrees Celsius) we mounted VGA pot to Slot 1 Celeron 300A with screw clamp, insulated Slot 1 with kneaded eraser, towel paper and vaseline.

Next we taped Slot 1 VID pins (A119, A121 & B119) to raise the processor’s default voltage from 2,0V to 2,2V which allowed us to raise VCORE from BIOS to 2,7 V.

Mixture of dry ice and acetone cooled the pot down to -65 degrees Celsius and temperature raised to -60 during the SuperPI 1M benchmark.

We managed to get our Celeron 300A running @ 721 MHz (+140 % overclock) and got it validated with CPU-Z.

Benchmarks were stable around 700 MHz and we managed to run World Records in ”short” SuperPI 1M, Pifast and wPrime 32M tests. Our SuperPI 1M result was 2min 32sec which is a rather long wait since today’s fastest systems run it in 5 seconds. See the list of World Records here.

This was fun, next we’ll test Celeron 300A with liquid nitrogen (-196 degress Celsius). Might take a year or two but stay tuned :-)



  1. Retro-ylikellotusta: ME-tulosten metsästystä Celeron 300A:lla
  2. Alustan ja käyttöjärjestelmän valmistelu Coppermine Pentium III 600:lla (100)
  3. Kuivajäätestit
  4. ME-tulokset ja loppusanat
  5. Retro overclocking: World Records with legendary Celeron 300A

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