Biostar M6TWG Overclock Celeron II 600

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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
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
change the core voltage on the MOBO through jumpers?

Im still new at overclocking.




Re: Biostar M6TWG Overclock Celeron II 600

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.

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

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.

Phil Weldon

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Re: Biostar M6TWG Overclock Celeron II 600

Phil Weldon wrote:
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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.

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