Overlooking this fact is what causes the dumbfounded nature of individuals who buy a lightning fast processor and end up with a slow machine and don't understand why?
The speed of a PC is determined by the speed of its slowest component. That component is considered your 'bottleneck'
The Front Side Bus [FSB] is the main connecting point to the CPU for Data to pass between the CPU and the Northbridge [1] its speed is measured in Hz. The average speed of a FSB is in MHz and on average the speed of the CPU is capped at 8x the FSB rate.
So if you had a 100 MHz FSB and a 3.2GHz processor your maximum speed would be 800 MHz. Making the bulk of the processing capacity of the CPU useless. A 3.2 GHz processor would need at least a 400 Mhz FSB in order to use its full processing capacity.
Read the section of the article linked [2] on the relation of the FSB rate to the speed of other components.
Memory in the Form of RAM also has a Hz rate. Again the average rate is in MHz and the speed of the RAM is linked to the speed of the FSB, they are interdependent.
The higher the Hz the faster each component will be but if you don't pair components off with rates that cooperate you will end up with a slow machine.