Retro Overclocking

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Overclocking the PII 266 – Mathieu

Ed Note: Mathieu sent this in and it reminded be about “overclocking in a time far, far away….” Do a search and you’ll be surprised how many of these are still around – cheap internet box??

My name is Mathieu and I send you this mail today to publish what I succeeded to do with a 266 Mhz Pentium II.

I watched the database some months ago and discovered I was the lucky N°1 in this category, but when checked again a few days ago, I saw I had been passed by with more recent motherboards allowing FSB frequencies higher than mine. I decided to submit my report anyway because there’s a point on which I am still the first, it seems: I used no CPU extra cooling.

I can say it is rock stable under Windows 98 / Windows 2000 PRO / Linux Mandrake 8.2, since it’s been running since JUNE 2003 with these OS’s for a wide type of uses (games, office work, compilation). The only one that didn’t run correctly was video encoding (maybe overheating or more probably bus instability).

I tried to observe the effects and paths of the dissipated heat and altered my box consequently (punched holes mainly) to allow passive air flow and it worked. I reached a common 338 MHz global frequency with the standard heat dissipation Intel nicely riveted on the CPU case. I used 512 Mb 133 Mhz SDRAM, which revealed some bus troubles as it was never considered by the BIOS to be more than 320 Mb (!?) and 64 Mb PC100 SDRAM, which ran perfectly alone as well as combined.

Another weird fact was that my FUJITSU 1623TAU 1,7Gb hard drive was always recognised by the BIOS as having a size of 524 Mb (as it would be with a messy partition table, I guess) but always ran perfectly – was it the fact it was holding only Linux Ext3fs partitions?…


I can assure a normal function if the ACPI system is properly configured (eg, Auto-standby after 5 mins and hibernation after 10 mins) because leaving Windows 2000 idle for tenths of minutes sometimes led the system to overheat; not under Windows 9x/Me with soft RAIN and not under Linux, because it’s on the way to perfection…. 😉

Here are the details:

  • CPU: Pentium II MMX 266 MHz (SL2HE) with Aluminium dissipator
  • RAM: 512 Mb PC133
  • GRAPHICS: ATI Xpert@Play 98 AGP 2x RAM 8 Mb
  • Display: UNISYS EVG2000E XGA
  • Hard-Drives QUANTUM Fireball 6 4Gb UDMA33 IDE,
    WESTERN DIGITAL WD200BB 20Gb 7200rpm UDMA 100 IDE,
    FUJITSU 1623TAU 1,7Gb DMA
  • Optical Drive: SAMSUNG CD-R/W 8.4.32 IDE PIO4
  • Expansion boards: Guillemot Maxi Studio ISIS PCI,
    REALTEK NE2000 compatible PCI,
    Pinnacle PCTV PCI,
    Realtek NE2000 compatible ISA,
    SoundBlaster AWE64 ISA
  • CASE: ATX big tower with additional holes
  • BIOS: FPU x Multiplier – 83,5 MHz x 4.0 = 338 MHz
  • Spread Spectrum: ON or OFF changed nothing

All bus options were on and the IDE settings were saved to avoid detection at boot

In fact I publish this overclocking report today because tomorrow the computer will be disassembled and later being sent as donation to an isolated school in Africa, not that they also want to play with frequencies, just because after this test period I have no doubt the PII CPU at it’s normal frequency of 266 MHz is 100% able to bear the ambient heat in this region. With repeated Coca-Cola spillage, it also proved to be moisture friendly too!

Thank you for your cool site which really helped me in my past overclocking experiences and probably will again when I find an interesting SMP system to freak with.

Best regards –


Mathieu – France



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