"You can choose the ratio among 2:3:1, 3:3:1, 4:3:1, 4:4:1 (within the range of external clock from 50~96MHz), or 3:3:1, 4:3:1, 4:4:1 (within the rage of external clock from 97~140MHz), or 4:3:1, 4:4:1 (within the range of external clock from 140~250MHz)
Take the external clock of 66MHz for example:
If you choose the FSB ratio of 2:3:1, the figure of CPU:SDRAM:PCI will be all divided by 2, that is: CPU= 66x2/2=66MHz, SDRAM= 66x3/2=100MHz , PCI= 66x1/2=33MHz
And if you choose the ratio of4:3:1, the figure of CPU:SDRAM:PCI will be all divided by 4, that is: CPU= 66x4/4=66MHz, SDRAM= 66x3/4=50MHz, PCI= 66x1/4=17MHz"