what physically determines the speed of a processor?
In: Technology
To add on to what others have said: the speed of the clock determines how frequently the transistors on the CPU will switch. Switching takes some power to do.
Also, a big limiting factor to how fast you can clock your CPU is actually not limited by the transistors. It’s the wires going from one place to another. A longer wire will be slower to carry electricity than a shorter wire. Transistors need some time to charge to turn on and off. More voltage will do this quicker, longer wires will slow this down.
The transistors themselves can actually switch WAYYYY faster than a few GHz like you see in your typical processor. For example, a smaller part of your processor, like a divider, multiplier, or a more complex function, may be clocking in the realm of 30-40 GHz. And that’s not all. A CMOS ring oscillator can have transistors switching at a rate of over 200 GHz!
When you combine these one after another, you will need to give some time for the signals to hop from one transistor to the next. And that’s where you start making larger and larger building blocks for your processor, and those building blocks will each need some time for the signal to come in, go through, and leave.
I could go on all day, but that’s a very rough explanation.
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