Archived from groups: alt.comp.hardware.overclocking (
More info?)
Phil Weldon wrote:
> This is not going to be a short answer.
>
> If you just want to jump in with no thought for the consequences, the
> first, inexpensive, step you should try is to set the ratio of the
> FrontSide Bus (what your BIOS evidently calls 'Host') and the PCI
> Clock so that the PCI Clock is less than 37 MHz.
>
> ***
> The FIRST thing to do when overclocking equipment you alread have is
> read the manual for your motherboard (either you already have it, or
> you can download most motherboard manuals from the manufacturer
> website. The Biostar M6TWG motherboard evidently has no settings,
> either in the BIOS, or by jumpers on the motherboard to change CPU
> voltage settings.
> There is a jumper to choose between a FrontSide Bus frequency of 66
> MHz and 100 MHz.
>
> There is a BIOS setting for Memory timings, but unless you have
> REALLY slow memory (certified only for 66 MHz) these settings should
> just be left at. default.
>
> There is a BIOS setting for CPU Host/PCI Clock and there is a setting
> for CPU ratio. The CPU ratio should be a ratio between the PCI bus
> speed and the FrontSide Bus speed. It should be set so that the PCI
> clock is less than 36 MHz (i.e. if the FrontSide bus speed is 100
> MHz, the ratio should be set to 1/3 [or 3], if the FrontSide Bus
> speed is 66 MHz, the ratio should be set to 1/2 [or 2], if the
> FrontSide Bus speed is over 75 MHz, then the ratio has to be set to
> 1/3 [or 3]). Some BIOS use fractions, some use whole numbers for the
> ratio setting. On the other hand, translations for motherboards tend
> to leave a lot of ambiguity. You will just have to work out whether
> the 'CPU Ratio' is just the CPU multiplier (which you can't change,
> it is fixed inside the CPU.) If the 'CPU Host/ PCI Clock' ratio sets
> the frequency relationship between the FrontSide Bus, then it would
> seem that the 'CPU ratio' could only be the 'CPU multiplier", and
> can't be changed (or, if, as in some BIOS, it CAN be changed, the
> change has NO effect (except for Intel PC compatible CPUs prior to
> midrange Pentium II CPUs.)
> Evidently you are setting the FrontSide Bus speed to 75 MHz so that
> the locked in multiplier of 9 X for the Celeron 600 clocks at 75 MHz
> X 9 = 675 MHz.
>
> If the PCI bus is set to much above its stock speed of 33 MHz
> corruption of hard drive data will begin to occur, both on reads and,
> what is worse, writes. In the far past, some motherboards and hard
> drives seemed to work at PCI bus speeds as high as 40 MHz, but that
> was taking a chance. (Nearly every peripheral other than the AGP
> card for a PC compatible computer is hung on the PCI bus; there
> really is nothing to be gained by overclocking the PCI bus, and lots
> to lose.)
> Intel CPUs are very overclockable as a rule. Some overclock
> amazingly well (especially those of mid-range speeds of a particular
> manufacturing process) out of the box with stock voltages and
> cooling, requiring only increasing the FrontSide Bus speed and
> adjusting the PCI bus ratio (and AGP bus ratio) to attain stable
> operation. Some require increasing the CPU voltage by less than 20%
> (more than that risks immediate destruction of the CPU.) Some,
> especially for extreme overclocks, require better than stock cooling.
> Experience has shown that there is a trade off of temperature
> overhead and clock speed overhead.
> Depending on the symptoms that show up when you try to overclock
> slightly above 675 MHz, the problem you experience may be the result
> of a too high PCI bus speed.
>
> Or it could be that your particular CPU chip requires a small voltage
> boost.
> Or it could be that your particular CPU chip will not reach a higher
> overclock no matter what you do.
>
> ***
> The first, inexpensive step you should try is to set the ratio of the
> FrontSide Bus (what your BIOS evidently calls 'Host') and the PCI
> Clock so that the PCI Clock is less than 37 MHz.
>
> The ideal overclock for the Celeron 600 is to change the FrontSide
> Bus speed to 100 MHz and set the PCI bus speed to 1/3 the FrontSide
> Bus speed. This ensures that the PCI bus speed is correct and gives
> a very nice overclock of 50% (900 MHz.) This should be easily
> attainable, but raising the CPU voltage may be neccessary. At any
> rate, overclocking should be approached step by step. Try smaller
> increases in the FrontSide Bus Speed (if possible) rather than
> jumping directly from 66 MHz to 100 MHz.
> There are ways to mechanicaly change the setting of the CPU core
> voltage by wiring CPU pins together, but that really isn't something
> you want to risk in starting out.
>
> The best overclocking experiences come from using an overclocking
> friendly motherboard with a good reputation, a CPU model known to be
> a good overclocker, and a high quality power supply. Try to
> eliminate as many potentil weak spots as possible before begining to
> operate the CPU above specifications. It will save a lot of
> frustration.
Nice answer Phil. Where do you get the patience?
I have two Intel Celeron 600 Coppermines here, a cB0 and a cC0 stepping and
both will run just fine at 900MHz. However they both need respectable vcore
boosts to do so, the cC0 less so than the cB0. It's a shame that they're
both sitting in a drawer, they're good CPUs. However, since I got adapters
and Tualatins my three BX boards are all running Celeron Tuis now.
--
~misfit~
> "r3sil3" <r3sil3.1si2ya@hardwarebanter.com> wrote in message
> news:r3sil3.1si2ya@hardwarebanter.com...
>>
>> Ok, I'm trying to figure out how to overclock my PC.
>> I know, I know, its slow and old.
>>
>> I have went into Bios, which is by Award, and i can change
>> CPU/DIMM/and some other setting, but the most i can get it to oc is
>> 675. I cant change the core voltage through the BIOS, does anyone know
>> how I could change the core voltage on the MOBO through jumpers?
>>
>> Im still new at overclocking.
>>
>> Thanks
>>
>> r3sil3
>>
>>
>> --
>> r3sil3
Facebook
Twitter
Instagram