Why do CPUs need to tick?

Duke_Leto

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Nov 24, 2015
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In as much detail and technical words as you can use, why do CPUs need to tick?

You can make a circuit that doesn't tick, so why do CPUs tick?
 
Solution
It's actually like this:
Oscillator determines frequency of DC current being turned on and off. On an oscilloscope you would see a square wave all above the base line. Processor is made of millions of transistors (switches) and for each "tick" if no current passes thru it it's a 0, if there is current 1 is registered. (either 0 or 1 make one bit). If straight DC is used without it being cut to 0v at exact intervals, all you would get i 1 (ones) and it can't do nothing but heat up. So ticks are necessary to make it binary system instead of a small heater.
Once upon a time there was a crystal on MB that determined frequency but now a PLL (Phase Locked Loop) in the processor itself that does that.
What do you mean when you say CPUs tick?

Intel has a tick-tock cadence to their CPU releases, where the tick is a die shrink and the tock is a new architecture. That is just their corporate plan.

Or perhaps you mean the system clock, which some still call ticks, that operate at 200MHz or more (so hundreds of millions of ticks per second) and numerous instructions per clock cycle?

 
Not exactly. There is no frequency for a DC circuit -- only for an AC circuit, and yes CPUs run at a frequency, although it is more complex with a system clock and different multipliers for different subsystems.

edit: p.s is this a homework question or are you just curious?

 


Consider 2 different CPU's that are "3.4Ghz". That is the frequency.
But CPU A is 2 core, CPU B is 4 core.

Does CPU B run twice as fast as CPU A? No. But CPU B get more work done, per clock cycle, than CPU A. Even though they run at the same 'frequency'.
 
Not everything needs a clock, but computers cannot operate without a common (Core)clock.

Start by searching for a "Latch" circuit you will find that if you have an input change it will not change the output until you send a clock signal.
If you find a detailed schematic you will see the clock circuit. (I say search for a latch because it is very simple and still has a clock usually)
All chips have this circuit, without it you would not be able to synchronize a complicated circuit and you would error very fast even on a simple logic circuit.
 
It's actually like this:
Oscillator determines frequency of DC current being turned on and off. On an oscilloscope you would see a square wave all above the base line. Processor is made of millions of transistors (switches) and for each "tick" if no current passes thru it it's a 0, if there is current 1 is registered. (either 0 or 1 make one bit). If straight DC is used without it being cut to 0v at exact intervals, all you would get i 1 (ones) and it can't do nothing but heat up. So ticks are necessary to make it binary system instead of a small heater.
Once upon a time there was a crystal on MB that determined frequency but now a PLL (Phase Locked Loop) in the processor itself that does that.
 
Solution