Abit SL6 User Manual page 36

3-6
FSB has been set, all of the other components will be able derive their proper
operating frequencies.
For example: If you have a CPU rated for a 100MHz FSB, the operating frequencies
for the proper values for the FSB : SDRAM : PCI for your CPU would be
calculated thusly:
®
Pentium III CPU with 100MHz FSB running at 500MHz:
100MHz (3:3:1) (each divided by 3) (FSB) 100MHz : (SDRAM) 100MHz : (PCI)
33MHz
CPU FSB value = 100MHz x 1 = 100MHz (proper FSB value for this CPU)
SDRAM value = FSB 100MHz x 1 = 100MHz (proper value for PC100 RAM)
PCI value = FSB 100MHz x 1/3 = 33MHz (proper value for PCI bus)
So that for this example above you can see that the x1, x1, x 1/3 values in
relation to the FSB can be written as
Additionally, for the working value of the CPU (in this case a Pentium® III 500MHz
you calculate it like this:
CPU working value = FSB 100MHz x 5 = 500MHz (proper value for this CPU)
Also, the AGP value is derived from the PCI value so that:
AGP value = PCI value (33MHz) x 2 or (4) = 66MHz or (132MHz) (proper
value for AGP bus) For a 2x AGP it works at double the speed of the PCI bus,
and four times for 4x AGP.
When the FSB is above 100MHz, such as 133MHz, you can choose a PCI divider of
4, again giving you the proper 33MHz value.
Now, in the BIOS they do not write dividers in fractions but rather in whole integers,
so that again for the 100MHz FSB example,
above it looks like this:
100MHz (3:3:1)
But you need to remember that each value is also divided by 3
you can look at it as if it were:
100MHz (3:3:1) each divided by 3
but you can also look at it as if it were:
SL6
100MHz (1: 1: 1/3)
100MHz (1: 1: 1/3)
Chapter3
,
in the table