one measure of computer performance

one measure of computer performance is bus bandwidth.

that is how fast the buses are transferring information (opcode,operands) between the CPU and memory and peripheral devices.

Now one might ask why one should care how fast buses transfer information between the CPU and outside, as long as the CPU is working as fast as it can.

the problem is that the CPU cannot process information that it does not have. in other words,

the speed of the CPU must be matched with the higher bus bandwidth; otherwise, there is no use for a fast CPU.

this is like driving a Porsche or Ferrari in first gear; it is a terrible under of CPU power.