I’m confused. I did some research online, and learned that cpu’s can essentially double has a hotplate, because 99-100% of electricity consumed is turned into heat. how? doesn’t the cpu use energy to make calcuations and render things? I’m real confused.
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Imagine you have a billion jump ropes in a room. Then they all start shaking. The room will get hot an noisy.
This is just like a cpu, the billions of transistors and trace lines are moving electricity, they get hot and excited moving those electrons in such a tiny place.
>doesn’t the cpu use energy to make calculations and render things?
Yes.
But you know the law of conservation of energy, the one that states that energy cannot be created or destroyed? That means whatever electrical energy you put into the CPU *must* be turned into some other form of energy.
When you’re talking about the CPU “using” energy to perform calculations, in a *physical* sense, what is it actually doing? The answer is, not much. It’s not turning electrical energy into kinetic energy, the way a car would. It’s not performing work on itself, such as lifting itself onto a higher shelf. It’s not even using the energy to drive airflow to cool itself – that’s the job of the fans, not the CPU. Instead, all of the “physical” aspects of what it’s actually doing is just sending out electrical signals to various parts on the motherboard, which barely uses *any* electrical energy.
As per the law of conservation of energy, the remainder of the energy supplied to the CPU, which is to say, practically all of it, must be converted into a different form. That different form is heat, which the CPU converts it into through various leakage currents and resistive losses and other internal losses.
All energy goes to heat eventually and data is very very light so it can’t absorb much of the energy.
“Using” energy doesn’t mean it goes away. It makes the energy less usable. So the electricity coming in has energy that is easy to do stuff with. The heat is still energy, but it’s so spread out that it’s not really usable.
Similarly, the energy hitting the earth by the sun is roughly the same amount as it gives off. But the light we get is more usable that we give off. Like we might get 1 photons with 100 units of energy and then give off 100 photons with 1unit of energy.
Your CPU is essentially a very fancy toaster oven. The basic principles are the same…it’s just moving electrons through a wire in a very specific way.
The CPU making it’s “decisions” is based on the *flow* of electricity through it, not the consumption of it. Like a water wheel, it doesn’t actually consume water as it does it’s job.
That said, so much power flowing in a small area is going to heat up the chip in a way you can kind of think of like friction. That energy is lost. Therefore, of the energy that is lost in a computer chip, it is mostly through heat.
Switching. It switches tiny transistors which become short circuits with a little resitance. Current^2 x resistance equals heat that needs dissipation. The switching is so fast it may as well be continuous. Overclockers increase switch frequency and voltage? So more voltage more current, fast switching more current through resistance to generate heat. You can turn your light bulb on, then touch it after 10 minutes, turn it on for minute then off for 1 mi ute. But if you switch it on and off 100000 times a second its pretty equivalent to continuous current and power drop
Processors are actually a bunch of sensors that measure voltages in circuits and wires. Because circuits and wires have resistance they also create heat
All “energy used” is converted to heat. That is the end state for all energy.
If the CPU does X and draws Y watts of power to do it, X will happen and it will radiate Y watts worth of heat.
all electricity consumed becomes heat, basically.
Used to move a fan? Heat in the motor, and then it move the blaes, which move the air. That air doesn’t move perpetually. It slows down and stops. What stops it? Friction. What is that kinetic energy turned into as it stops? Heat.
Used to execution CPU instructions? Internal resistance at every little itty bitty transistor, every little bit flipped or flopped, that’s resistance and heat.
Every time you ask electricity to *do* something, there is wasted energy. Heat.
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