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> The Abit BP6 was legendary with enthusiasts because it let them make a dual CPU system with cheap Celeron CPUs. And 2 celerons were cheaper than a CPU with d

> The Abit BP6 was legendary with enthusiasts because it let them make a dual CPU system with cheap Celeron CPUs. And 2 celerons were cheaper than a CPU with double the performance?

SirFatty 10mo ago
You could over-clock the Celeron and get even more performance. Both the slot-1 and ZIF style...
riffic 10mo ago
they may have been, yes. back in those days, a CPU with multiple cores were meant for the server or enterprise workstation market and priced accordingly. Celerons were consumer-grade budget kit.
- einr 10mo ago
  There were zero multi-core x86 CPUs, server or otherwise, back in those days.
ThrowawayR2 10mo ago
Just by the release MSRP: 2x Celeron 366 MHz @ $123 each - https://en.wikipedia.org/wiki/List_of_Intel_Celeron_processors https://en.wikipedia.org/wiki/List_of_Intel_Celeron_processo... 1x Pentium III 733 MHz @ $776 - https://en.wikipedia.org/wiki/List_of_Intel_Pentium_III_processors https://en.wikipedia.org/wiki/List_of_Intel_Pentium_III_proc... And that's assuming that performance scales linearly with clock frequency (which it doesn't).
- ckozlowski 10mo ago
  Thanks for looking up the numbers! That would be quite the "budget" SMP build. The 366MHz "Mendocino" was based on the prior Pentium II core I believe. So quite the disparity in single-threaded workloads.
- phil21 10mo ago
  The Celeron 300A was the one most folks would go after for this. I don't recall the exact retail pricing at the time, but they were more or less guaranteed to overclock to 450mhz and be fully stable. Typically retail pricing could be had at discount to the published wholesale pricing within a couple months of release due to how quickly the market moved back then. These were competing with PII processors in 1998, and for folks who wanted to go dual CPU it was the way to go. There was a whole cottage industry of folks modding these CPUs as a small side hustle for people who were not comfortable with soldering onto CPU pins if you wanted to put these into a SMP system. Performance really did mostly scale linearly with clock speed back then - but for a single CPU. The dual CPU setups were not nearly as efficient due to software not being as multi-threaded as it is today. The big win were folks with two monitors (rare!) who could run apps on their second monitor while playing games on the first. Typically you would only see frame-rate increases with CPU clock - and of course the very start of the serious 3D accelerator (3dfx, nvidia, ATI) scene back then. It was certainly the golden age of enthusiast computing - especially for gaming.
  - ndiddy 10mo ago
    > There was a whole cottage industry of folks modding these CPUs as a small side hustle for people who were not comfortable with soldering onto CPU pins if you wanted to put these into a SMP system. When Intel switched from Slot 1 to Socket 370, there was a market for "slocket" adapters that allowed Slot 1 motherboards to take Socket 370 CPUs. The best of these adapters worked out a way to re-enable SMP on Celerons by tweaking the pin layout to disable the lock Intel had added. What made the BP6 so popular is that it was a native dual-slot Socket 370 motherboard that had this modification built in so it could use unmodified dual Celerons out of the box. > Performance really did mostly scale linearly with clock speed back then - but for a single CPU. The dual CPU setups were not nearly as efficient due to software not being as multi-threaded as it is today. The big win were folks with two monitors (rare!) who could run apps on their second monitor while playing games on the first. Typically you would only see frame-rate increases with CPU clock - and of course the very start of the serious 3D accelerator (3dfx, nvidia, ATI) scene back then. Even if you only had one monitor, multitasking was FAR better on a dual-CPU machine than on a single CPU system. For example, if you were extracting a ZIP file, one CPU would get pegged at 100% but the system was still responsive due to the second CPU not having any utilization. If you use a dual-Celeron BP6 system, it's a much nicer and more modern feeling experience than using a single-PII system even with the faster CPU with more cache.
- giobox 10mo ago
  The P3s often cost more than the MSRP at retail too back in the day, as they were supply constrained in period for various reasons, which heavily contributed to the popularity of BP6 builds with enthusiasts. Intel really struggled to ramp up P3 production.
ckozlowski 10mo ago
Yes, because there weren't really CPUs then that had double the performance. 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. Workloads have different constraints however, and simply doubling cache, clock speed, or memory bandwidth doesn't necessarily double performance, especially when running more than one application at once. Keep in mind, this is Windows 98 /NT/2000 era here. Symmetric multi-processing (SMP) could be of huge benefit however, far more than simple doubling any of the above factors. Running two threads at once was unheard of on the desktop. These were usually reserved for higher-binned parts, like full-fledged Pentium workstations and Xeons (usually the latter.) But Abit's board gave users a taste of that capability on a comparative budget. Were two cheaper than a single fast CPU? Probably not in all cases (depends on speeds). But Abit's board gave users an option in between a single fast Pentium and a orders of magnitude more professional workstation: A pair of cheaper CPUs for desktop SMP. And that was in reach of more people. In short, two Celerons were probably more expensive than a single fast Pentium, but having SMP meant being able to run certain workloads faster or more workloads at once at a time when any other SMP system would have cost tons.
- rconti 10mo ago
  Going from a single CPU to a dual CPU would, in theory, double performance _at best_. In other words, only under workloads that supported multithreading perfectly. But in the real world, the perceived performance improvement was more than doubling. The responsiveness of your machine might seem 10 or 100x improved, because suddenly that blocking process is no longer blocking the new process you're trying to launch, or your user interface, or whatever.
  - keyringlight 10mo ago
    One thing I've noticed is that the phrase "CPU hog" has faded from common usage
    - MontyCarloHall 10mo ago
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 ago
  Many, 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 ago
  Not "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 ago
    What CPU had double the performance of a (top-of-the-line) PII CPU at the time?
  - throwway120385 10mo ago
    On the Slot 1 version of that processor you could disable the multiplier lock by cutting one of the pins on the slot.
  - tpm 10mo ago
    IIRC 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.

> The Abit BP6 was legendary with enthusiasts because it let them make a dual CPU system with cheap Celeron CPUs. And 2 celerons were cheaper than a CPU with double the performance?

SirFatty 10mo ago

You could over-clock the Celeron and get even more performance. Both the slot-1 and ZIF style...

riffic 10mo ago

they may have been, yes. back in those days, a CPU with multiple cores were meant for the server or enterprise workstation market and priced accordingly. Celerons were consumer-grade budget kit.

einr 10mo ago
There were zero multi-core x86 CPUs, server or otherwise, back in those days.

ThrowawayR2 10mo ago

Just by the release MSRP: 2x Celeron 366 MHz @ $123 each - https://en.wikipedia.org/wiki/List_of_Intel_Celeron_processors https://en.wikipedia.org/wiki/List_of_Intel_Celeron_processo... 1x Pentium III 733 MHz @ $776 - https://en.wikipedia.org/wiki/List_of_Intel_Pentium_III_processors https://en.wikipedia.org/wiki/List_of_Intel_Pentium_III_proc... And that's assuming that performance scales linearly with clock frequency (which it doesn't).

ckozlowski 10mo ago
Thanks for looking up the numbers! That would be quite the "budget" SMP build. The 366MHz "Mendocino" was based on the prior Pentium II core I believe. So quite the disparity in single-threaded workloads.
phil21 10mo ago
The Celeron 300A was the one most folks would go after for this. I don't recall the exact retail pricing at the time, but they were more or less guaranteed to overclock to 450mhz and be fully stable. Typically retail pricing could be had at discount to the published wholesale pricing within a couple months of release due to how quickly the market moved back then. These were competing with PII processors in 1998, and for folks who wanted to go dual CPU it was the way to go. There was a whole cottage industry of folks modding these CPUs as a small side hustle for people who were not comfortable with soldering onto CPU pins if you wanted to put these into a SMP system. Performance really did mostly scale linearly with clock speed back then - but for a single CPU. The dual CPU setups were not nearly as efficient due to software not being as multi-threaded as it is today. The big win were folks with two monitors (rare!) who could run apps on their second monitor while playing games on the first. Typically you would only see frame-rate increases with CPU clock - and of course the very start of the serious 3D accelerator (3dfx, nvidia, ATI) scene back then. It was certainly the golden age of enthusiast computing - especially for gaming.
- ndiddy 10mo ago
  > There was a whole cottage industry of folks modding these CPUs as a small side hustle for people who were not comfortable with soldering onto CPU pins if you wanted to put these into a SMP system. When Intel switched from Slot 1 to Socket 370, there was a market for "slocket" adapters that allowed Slot 1 motherboards to take Socket 370 CPUs. The best of these adapters worked out a way to re-enable SMP on Celerons by tweaking the pin layout to disable the lock Intel had added. What made the BP6 so popular is that it was a native dual-slot Socket 370 motherboard that had this modification built in so it could use unmodified dual Celerons out of the box. > Performance really did mostly scale linearly with clock speed back then - but for a single CPU. The dual CPU setups were not nearly as efficient due to software not being as multi-threaded as it is today. The big win were folks with two monitors (rare!) who could run apps on their second monitor while playing games on the first. Typically you would only see frame-rate increases with CPU clock - and of course the very start of the serious 3D accelerator (3dfx, nvidia, ATI) scene back then. Even if you only had one monitor, multitasking was FAR better on a dual-CPU machine than on a single CPU system. For example, if you were extracting a ZIP file, one CPU would get pegged at 100% but the system was still responsive due to the second CPU not having any utilization. If you use a dual-Celeron BP6 system, it's a much nicer and more modern feeling experience than using a single-PII system even with the faster CPU with more cache.
giobox 10mo ago
The P3s often cost more than the MSRP at retail too back in the day, as they were supply constrained in period for various reasons, which heavily contributed to the popularity of BP6 builds with enthusiasts. Intel really struggled to ramp up P3 production.

ckozlowski 10mo ago

Yes, because there weren't really CPUs then that had double the performance. 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. Workloads have different constraints however, and simply doubling cache, clock speed, or memory bandwidth doesn't necessarily double performance, especially when running more than one application at once. Keep in mind, this is Windows 98 /NT/2000 era here. Symmetric multi-processing (SMP) could be of huge benefit however, far more than simple doubling any of the above factors. Running two threads at once was unheard of on the desktop. These were usually reserved for higher-binned parts, like full-fledged Pentium workstations and Xeons (usually the latter.) But Abit's board gave users a taste of that capability on a comparative budget. Were two cheaper than a single fast CPU? Probably not in all cases (depends on speeds). But Abit's board gave users an option in between a single fast Pentium and a orders of magnitude more professional workstation: A pair of cheaper CPUs for desktop SMP. And that was in reach of more people. In short, two Celerons were probably more expensive than a single fast Pentium, but having SMP meant being able to run certain workloads faster or more workloads at once at a time when any other SMP system would have cost tons.

rconti 10mo ago
Going from a single CPU to a dual CPU would, in theory, double performance _at best_. In other words, only under workloads that supported multithreading perfectly. But in the real world, the perceived performance improvement was more than doubling. The responsiveness of your machine might seem 10 or 100x improved, because suddenly that blocking process is no longer blocking the new process you're trying to launch, or your user interface, or whatever.
- keyringlight 10mo ago
  One thing I've noticed is that the phrase "CPU hog" has faded from common usage
  - MontyCarloHall 10mo ago

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 ago
Many, 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 ago
Not "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 ago
  What CPU had double the performance of a (top-of-the-line) PII CPU at the time?
- throwway120385 10mo ago
  On the Slot 1 version of that processor you could disable the multiplier lock by cutting one of the pins on the slot.
- tpm 10mo ago
  IIRC 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.