The Asus P2B-S Rev 1.04. clock generator chip is an ICS 9250CF-08, capable of generating up to 150Mhz FSB. However, for reasons unknown, Asus crippled the chip by only installing 3 FSB jumper headers on the P2B-S Rev 1.04. mainboards. As a result, the mainboard cannot be jumpered for FSB speeds over 133Mhz, and the available 133Mhz setting overclocks the PCI bus to 44.33Mhz (FSB/3).
The table above shows the full range of FSB speeds supported by the ICS 9250CF-08 clock generator. Since Asus omitted the FS3 jumper, half these settings are unavailable - only the lower half of the table, where FS3 = 0, can be used. In order to enable the remaining settings, we must add the FS3 jumper header and a 10K ohm programming resistor in position R137A.
The FS3 header and R137A are missing in the picture above
The modified P2B-S Rev 1.04. was tested with a 1A Ghz Tualatin Celeron
CPU mounted on a Slot-T adapter, and a 256MB PC133 RAM module, both known
to operate reliably at 150Mhz FSB. Testing showed that the full range of FSB
settings supported by the ICS 9250CF-08 are now available, and that the mainboard
is stable at 150Mhz FSB.
Last updated March 22nd, 2003 by firstname.lastname@example.org