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For some reason you left off the part that explains that the Celeron had a PII core. > Socket 370 era Celeron processors had a Pentium II core, but Intel disab
by rconti 10mo ago
For some reason you left off the part that explains that the Celeron had a PII core.
> Socket 370 era Celeron processors had a Pentium II core, but Intel disabled the ability to change the multiplier to discourage overclocking
- ckozlowski 10mo agoMany, but not all. There were Coppermine derivatives eventually: https://www.cpu-world.com/CPUs/Celeron/TYPE-Celeron%20(Coppermine).html https://www.cpu-world.com/CPUs/Celeron/TYPE-Celeron%20(Coppe...
- yjftsjthsd-h 10mo agoNot "for some reason"; I didn't see it as relevant. If anything, it being a PII-lite with overclocking disabled makes it seem like a worse option? What am I missing here?
- rconti 10mo agoWhat CPU had double the performance of a (top-of-the-line) PII CPU at the time?
- throwway120385 10mo agoOn the Slot 1 version of that processor you could disable the multiplier lock by cutting one of the pins on the slot.
- tpm 10mo agoIIRC even with a locked multiplier you could overclock the CPU by increasing the base (fsb) frequency. So you would change the fsb freq from 66 to 100 MHz and this way get a 450 MHz CPU from a 300MHz one.
- lproven 10mo ago> What am I missing here? The whole point, really. Sorry, but you are. In the Pentium / PII era, CPU speed was the product of 2 factors: front side bus speed and clock multiplier. The original P5 and the 2nd gen P54 ran at FSB speed: 60 MHz or 66 MHz. The later Pentiums ran at an integer multiple: Pentium 120 = 60 MHz * 2 P 133 = 66 * 2 The PII ran at larger multipliers. I bought a PII 450 MHz on a Gigabyte motherboard that fit in my Baby-AT case, rather than the then-common ATX case. 450 = 100 MHz FSB * 4.5 That cost. Slower PIIs had a much slower 66 MHz FSB. PII 300 = 66 * 4.5 The Celeron had a locked multiplier but you could change the FSB. So, take a 300 MHz chip (running at a locked 4.5x the FSB) but put it on a much faster 100 MHz FSB at the same multiplier and you got a 450 MHz chip, and because it had a much smaller but on-die L2 cache, it was more likely to be stable. These Celerons came on a Slot 1 convertor and that needed to be modified to enable SMP operation. Pics: https://www.vogonswiki.com/index.php/Intel_Celeron_300A https://www.vogonswiki.com/index.php/Intel_Celeron_300A The famous BP6 motherboard ignored that setting and forced the uniprocessor-only Celeron to run in dual processor and overclocked it as well. So for 2 budget sub-£150 CPUs, rated for 300 MHz on a sluggish 66MHz FSB and one CPU only, you got a dual-processor 100MHz FSB machine with the raw single-core performance of something like a £500 processor. I never had one but you bet I heard about them and strongly considered it.
- ssl-3 10mo agoThey may have sought to discourage overclocking by locking the multiplier, but... People pretty routinely nearly doubled the clocks on Celeron 300As, anyway. :)
- vasac 10mo agoThe legend was that Celeron 300A CPUs packaged in Malaysia were more overclockable than those packaged in Costa Rica. I specifically hunted down a Malaysian one, and it happily ran at 450 MHz for years.
- rconti 10mo agoI remember that as well. The details elude me, but I seem to recall my 300A was running at 464.25mhz on an ABit B7.
- deltoidmaximus 10mo agoAnd then they left the overclocking back door wide open by giving the celerons a 66mhz FSB.