Reply

[Travis]

If you want to go higher with FSB you must disable pin on back side (B) number 21. There is numbers on processor so count number 21 on back side of the processor with peace of cellotape, pice of paper or nailvarnish. And voila hte FSB is unlocked.

[wild_andy_c]

oh dear me.

[wild_andy_c]

I presume from this thread that you are talking about a slot 1 celeron, p2 or p3 and what you are actually acheiving is altering the default voltage of the chip rather than altering the ability to unlock the FSB. Although altering the voltage may allow a chip to run at higher FSB's, pinning the chip does not unlock the FSB.

To give advice that may be incorrect, in an orphaned posting is not only a waste of effort, but also potentially dangerous for newbies / other users who may take heed of your advice and mis-interpret it causing damage to their system.

[SP]

wild_andy_c (Jul 04, 2001 02:09 p.m.):
I presume from this thread that you are talking about a slot 1 celeron, p2 or p3 and what you are actually acheiving is altering the default voltage of the chip rather than altering the ability to unlock the FSB. Although altering the voltage may allow a chip to run at higher FSB's, pinning the chip does not unlock the FSB.

To give advice that may be incorrect, in an orphaned posting is not only a waste of effort, but also potentially dangerous for newbies / other users who may take heed of your advice and mis-interpret it causing damage to their system.


Actually he's quite right. For a 66Mhz FSB processor taping over or painting pin B21 will identify it as a 100Mhz FSB processor to the motherboard. B21 is the Bsel0 signal that distinguishes to the motherboards whether the CPU is a 66Mhz FSB processor or not. On a 66Mhz FSB processor, like a celeron, this pin will be internally pulled down to ground. The motherboard has a pull up resistor on this line. When a 66Mhz FSB processor is installed it pulls the Bsel0 down to ground or 0 and this tells the clock generator to run the FSB at 66Mhz. When you break the connection by taping, painting, or otherwise insulating this pin it then goes high or 1 indicating to the clock generator that a 100Mhz CPU is installed. Of course this only works for overclocking a 66Mhz FSB processor. There is another pin called Bsel1 that distinguishes between 100Mhz and 133Mhz FSB cpus. It works on the same principals. Bsel1 is A14 on a slot 1 processor. So, you can tape pin A14 on a 100Mhz FSB processor and force it to run at 133Mhz FSB in much the same way. Also, FCPGA cpus have pins that carry the same signals. So, something along these lines would also work with them as well. You just have to find the right location of these pins.

For more specific details go here (http://developer.intel.com/design/PentiumIII/datashts/) and download "Pentium® III Processor for the SC242 at 450 MHz to 1.13 GHz Datasheet" and "Pentium® III Processor for the PGA370 Socket at 500 MHz to 1.13 GHz Datasheet". It's all in there as well as which pins control voltage. In the Sc242 datasheet (sc242 = slot 1) Bsel0 and Bsel1 are covered on about page 22.

It should however, be noted here that we are talking about FSB and not multipliers. Some people seem to easily get mistaken into thinking that what we're talking about here somehow has something to do with unlocking the multiplier. It doesn't and that's not what we're talking about. There is NO way to unlock multipliers once they are locked by Intel. They are locked internally by burning out circuits inside the chip.

Anyway most motherboards allow FSB adjustments anyway. So, this is usually not necessary, but if you happen to have a motherboard that doesn't allow you to alter the FSB this method of pin taping or insulating can be useful. On those motherboards with no FSb adjustment it's sometimes the only way to overclock without modifying the motherboards clock genrator circuitry.