So what exactly does the frontside bus speed relate to, if anything?
Good question. It used to be that all components of a PC were timed by a
clock, and ran at the same speed. Think of a drill sergeant calling cadence
while all the troops are marching. But modern CPUs run much faster than the
clock, so they need multipliers, also. (that is, they run at some MULTIPLE
of the clock speed). Also, the clock in some cases is too fast, so some
components run at a DIVISION of the clock speed. For convenience of
customers, many mainboard manufacturers are now using chipsets that allow
different components to run at different clock speeds. That's how you get a
200MHz CPU running just fine with 166MHz (DDR333) RAM, for example. This is
possible as the chipset will act as kind of a buffer between them,
communicating at different speeds with different components.
Typically, most components have their timing related IN SOME MANNER to the
front side bus speed, which is what the CPU is using to communicate with the
chipset, and with everything else. Think of this bus as a hotline tied to
everything, though not necessarily directly tied to everything.
Where overclockers get in trouble (if they don't know what they are doing)
is that they don't realize that changing the FSB will change everything. A
common problem is, cranking up FSB too far can overclock your PCI bus (even
though it's slower, it's still related to the FSB speed), and cause massive
system instability. That's just one example of a problem with overclocking.
This is where BIOS settings that are overclocker friendly come in. If you
really want to tweak the FSB, you've got to be able to control speeds that
other components that get timing related to FSB are operating at. -Dave
