what physically determines the speed of a processor?
In: Technology
Quick background. A computer program is a list of instructions. When you compile your code you generate a list of machine code instructions which are fed to the processor. The entire purpose of the processor is to execute those instructions.
Processors run at a set clock speed. The clock is a signal which transitions between high and low at a constant rate. This is the speed you see advertised when you buy a CPU, e g 4 GHz.
Processors execute instructions at a speed proportional to that clock speed. A simple processor might execute 1 instruction per clock cycle. In reality processors rarely ever finish an instruction in a single cycle, but I’m going to ignore that for simplicity. So in a simple processor if you double the clock speed you’re doubling the total speed of the processor.
So why not just jack up the clock speed to get an insanely fast processor? If you set the clock speed too high then the circuitry in the processor won’t be able to keep up. It takes time for transistors to switch and for the result of each instruction to be resolved. Manufacturers are constantly seeking ways to make circuits faster but it’s not easy.
Latest Answers