First post, by feipoa
- Rank
- l33t++
As many of you probably know, the PC Chips M919 v3.4B/F board implements an automatic 2/3 FSB-to-PCI multiplier when running the FSB at 40 MHz. This may also be true of earlier board revisions, e.g. v3.2 and earlier. Has anybody figured out how to prevent this from occurring? I am considering looking into this.
Unfortunately, this board uses the AMI BIOS, so even if we modify the BIOS to prevent this, there is the issue with correcting the checksum, which others here have reported problems with. Maybe there is something in AMISETUP or CTCHIP34 which can correct for this? Maybe there is a hardware-based, solder-on approach to prevent this from happening, perhaps by hard wiring (thereby bypassing the BIOS) the FSB clock to the PCI clock? Unfortunately, the latter would prevent the automatic 2/3 multiplier option from occurring when using a 50 MHz FSB, however perhaps the hardware mod could have a jumper that enables the bypass and re-enables it.
I am not sure where the 2/3 multiplication takes place - in the BIOS chip itself, or routed from the BIOS to the chipset. I do not believe the multiplication occurs on the PLL chip, like it does on SiS496-based boards. On SiS496-based boards, there is a PCI multiplier ("divisor") jumper which can be traced to the PLL clock generator chip.
Ideas/thoughts/suggestions?
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