What is the relation between processor (clock & FSB speed), motherboard
and RAM speed ?
CPU determines FSB speed. Motherboard chipset determines
the memory bus speeds supported with any particular FSB
speed. In general, the memory bus speed support is for same
or 33MHz (clock rate) higher than the FSB speed, though in
modern times the chipsets have given a wider allowance for
faster or slower memory bus speeds even though most systems
are not set up in this way because there is either
diminishing return or lower performance from it.
What should be the speed of these 3 products to get maximum performance
? Please answer with a example from Intel and/or AMD based PC.
You don't choose it like this, rather buy the processor and
motherboard product line that the system budget supports.
Within this context they are details you do not use to
choose, rather are what you "get". In general, modern AMD
or Intel use 200MHz FSB (clock rate), which is either
DDR400, or QDR800 (Intel, so-called quad-pumped) so the
memory bus is then 200MHz clock rate.
Maximum performance means little, it has to be in context-
context of where an application's bottleneck is, context of
budget, context of whether system can (or should/shouldn't)
be overclocked, context of the necessary spec for the
components used - memory, cpu, chipset.
Given your question, it would be safer for you to completely
ignore these parameters and just do as the manufacturers
intend, buy what the budget allows based on the CPU model
name and from there you do not choose but are bound to the
associated, specified FSB & memory bus unless you choose to
overclock.
The most generic answer possible is- maximum performance
comes from all of these being as high as possible, but there
are finite limits to how high any given technology can
support and manufacturer imposed limits to preserve market
tiering, pricing structures.
