Overheating Cpu

[JayFoxRox]

Laurent: You should check your power supply then or send it in - somethink is going wrong. I had the BeagleBoard running for more than 20 hours straight with the cpu at room temp. at the default clock.

 

[Tor]

FWIW, the Nokia N800 doesn't get hot, exactly, and normally it doesn't even get warm, but when working particularly hard (e.g. streaming internet radio, which also sucks the battery faster than most other things (this is the built-in internet radio app, not vagalume/last.fm)), it definitely gets quite warm at the lump on the back. Not what I would call _hot_ though.

 

[Yannick]

While recharging, the battery will probably be hotter than the CPU/3D card

 

[Calmatory]

I don't think it even has a heatsink over the SoC, does it? ARM is very efficient. And by Efficient I mean less energy is released as HEAT.

All of the energy consumed by the CPU(and rest of the Pandora, for that matter) is released as HEAT. Remember that the energy does not disappear.

 

[WizardStan]

I don't think it even has a heatsink over the SoC, does it? ARM is very efficient. And by Efficient I mean less energy is released as HEAT.

All of the energy consumed by the CPU(and rest of the Pandora, for that matter) is released as HEAT. Remember that the energy does not disappear.

Wrong. Only excess energy is released as heat. Most of the electricity actually gets used to drive the CPU, flash, wifi, LCD, etc... Only a small amount of the total energy is lost due to inefficiencies causing a very small amount of heat to be generated.

 

[Mithrildor]

Craigix already told us (cant remember which topic) that it won't overhead before the battery is empty of power. Also you shouldnt be scared of this ARM produces way less heat than a x86 because it needs less power and uses this power better.

EDIT:

Just remembered this from school

P (Power in Watt) x t (time in seconds) = E (energy in Joule)

 

[Tor]

@WizardStan:
All of that ends up as heat eventually though. Calmatory is right. When you turn off the power everything is in the same place as before, it's not like you have converted electrical energy into potential energy by using it to lift something heavy up to a higher level, for example.
You can't pour energy into a computer and expect it to disappear like it was a black hole or something.

 

[bsamm97]

If it needs to be clocked higher for a more demanding game/application, would the software do it for you or would you need to manually increase it?

You would set a new maximum, and that maximum would be used if required. It doesn't happen automatically as you may prefer longer battery life than better performance.

Maybe someone can write a program to set CPU clock preferences for different applications

 

[nubie]

@WizardStan:
All of that ends up as heat eventually though. Calmatory is right. When you turn off the power everything is in the same place as before, it's not like you have converted electrical energy into potential energy by using it to lift something heavy up to a higher level, for example.
You can't pour energy into a computer and expect it to disappear like it was a black hole or something.

I don't think this is right, the electrons were moved, that equals work done.

 

[WizardStan]

@WizardStan:
All of that ends up as heat eventually though. Calmatory is right. When you turn off the power everything is in the same place as before, it's not like you have converted electrical energy into potential energy by using it to lift something heavy up to a higher level, for example.
You can't pour energy into a computer and expect it to disappear like it was a black hole or something.

It doesn't all turn into heat. There's many different forms of energy. Electricity can be converted to heat. Or into light. Or motion, or sound. Energy is used up as it passes through the CPU, causing transistors to tick over, energy which is not converted to heat. The energy is not lost, doesn't disappear, it is used to do work that does not necessarily result in heat.

 

[Mithrildor]

Only some of the energy turns in to heat the %of energy turned into heat is different for each electronical device but never all the energy will be turned into heat (Maybe some crashing device.)

 

[Tor]

Argh. Believe me, it will all end up as heat _eventually_. Including the light, when it gets absorbed somewhere (i.e. some of that will end up as heat on your walls, your retina, anywhere where the light gets absorbed. And it _will_ get absorbed.)

When you move something from A to B, and back again to A just to make sure that there's no difference in altitude (which would be potential energy), then what do you think happened to the energy used to move the thing forth and back? It was, in the end (from your muscles) dissipated as _heat_.

Every type of energy ends up as heat in the end.
You can have equipment which gets very little done because most of the energy is spent to heat a resistor directly (as in an inefficient voltage converter), or something that's more efficient, but the total energy used will end up as heat, all the same.

Edit: To elaborate a bit on the difference between an inefficient Pandora-type device and an efficient one, it's that the inefficient one needs even more power to get the same job done, i.e. it gets hotter because you have to provide more energy in the first place. But, as I said above, all of it ends up as heat eventually. It's more from the inefficient one because it needs more power.

 

[nubie]

Argh. Believe me, it will all end up as heat _eventually_. Including the light, when it gets absorbed somewhere (i.e. some of that will end up as heat on your walls, your retina, anywhere where the light gets absorbed. And it _will_ get absorbed.)

When you move something from A to B, and back again to A just to make sure that there's no difference in altitude (which would be potential energy), then what do you think happened to the energy used to move the thing forth and back? It was, in the end (from your muscles) dissipated as _heat_.

Every type of energy ends up as heat in the end.
You can have equipment which gets very little done because most of the energy is spent to heat a resistor directly (as in an inefficient voltage converter), or something that's more efficient, but the total energy used will end up as heat, all the same.

Edit: To elaborate a bit on the difference between an inefficient Pandora-type device and an efficient one, it's that the inefficient one needs even more power to get the same job done, i.e. it gets hotter because you have to provide more energy in the first place. But, as I said above, all of it ends up as heat eventually. It's more from the inefficient one because it needs more power.

Well, now I am curious, have you got any links that explain further? I will search on my own too.

Edit: http://www.eia.doe.gov/kids/energyfacts/sc...msofenergy.html

According to this page moving electrons is work, so energy is applied and electrons are moved, there isn't any "heat", except that from resistance to electron flow.

 

[WizardStan]

When you move something from A to B, and back again to A just to make sure that there's no difference in altitude (which would be potential energy), then what do you think happened to the energy used to move the thing forth and back? It was, in the end (from your muscles) dissipated as _heat_.

If you lift something up, it takes energy to fight against gravity. As it comes down, gravity is applying force downward. You effectively regain the energy. It doesn't necessarily become heat. It does in your muscles because the human body is designed to be partially inefficient in that way in order to keep us warm. A perfectly efficient system in a vacuum would produce absolutely no heat whatsoever, and the energy used would be perfectly aligned to gravity. For example, consider a perfect spring in a vacuum. Attach a weight to it such that it is in perfect balance, unmoving. Now, apply some energy: pull it down and let go. If the system is truly perfectly efficient, then it will bounce up and down forever, keeping the same energy that was originally put into it, with absolutely no loss. You can stop it by simply grabbing on again, but it takes exactly the same amount of energy to stop it as you had originally put into it.

QUOTE
Every type of energy ends up as heat in the end.
You can have equipment which gets very little done because most of the energy is spent to heat a resistor directly (as in an inefficient voltage converter), or something that's more efficient, but the total energy used will end up as heat, all the same.

I suggest you read a physics book. I'm not trying to sound condescending, seriously, but I don't know how to explain just how wrong you are without going back to absolute basics. Heat is not the end all of energy. Heat reacts in other ways (chemical, physical, and electrical) to produce motion, light, and sound again. There is no end to energy, it just keeps changing. The photons which leave the LCD hit a wall and are absorbed, producing heat. That heat disipates into the air, causing motion. That motion, if sufficiently amplified, is sound. That sound hits another wall which causes compression. That compression causes heat. And around and around we go.
It's an entirely moot discussion, at any rate. To say that the photons leaving the LCD will eventually become heat is a red herring anyway, since the conversation has always been about whether the Pandora itself will overheat. Energy that has already left the system that has not generated heat is no longer part of the equation, so I don't see why you've brought it up.

 

[nubie]

Just another day-to-day example from Google:


http://www.engineeringtoolbox.com/electric...ency-d_655.html

According to the info in that link electric motors are rated in efficiency, that is the ratio of kinetic energy to heat produced.

It becomes easier to grasp if you imagine a frictionless environment, or even a superconductor (these aren't really available to us, but super-chilled wires and ball-bearings are.)


The electrons motion is converted to magnetic force, and then into motion, not all heat.


In the processor electrons should flip a simple switch (transistor), and then return to the battery/power supply. Since the wires have resistance and the transistors have leakage you get heat.

 

[ldesnogu]

Laurent: You should check your power supply then or send it in - somethink is going wrong. I had the BeagleBoard running for more than 20 hours straight with the cpu at room temp. at the default clock.

Ouch, that indeed doesn't look good for my BB. I am using my USB hub power supply to power it... I will look for something better

 

[TheGoodDoktor]

I suggest you all read this:
http://en.wikipedia.org/wiki/Entropy

It may give you some insight into:
What is happening inside the Pandora Soc
What is happening in society as the world gets more densely populated.
How the universe will end.

 

[Phawx]

How do we reverse Entropy?

 

[audovoice]

Argh. Believe me, it will all end up as heat _eventually_. Including the light, when it gets absorbed somewhere (i.e. some of that will end up as heat on your walls, your retina, anywhere where the light gets absorbed. And it _will_ get absorbed.)

When you move something from A to B, and back again to A just to make sure that there's no difference in altitude (which would be potential energy), then what do you think happened to the energy used to move the thing forth and back? It was, in the end (from your muscles) dissipated as _heat_.

Every type of energy ends up as heat in the end.
You can have equipment which gets very little done because most of the energy is spent to heat a resistor directly (as in an inefficient voltage converter), or something that's more efficient, but the total energy used will end up as heat, all the same.

Edit: To elaborate a bit on the difference between an inefficient Pandora-type device and an efficient one, it's that the inefficient one needs even more power to get the same job done, i.e. it gets hotter because you have to provide more energy in the first place. But, as I said above, all of it ends up as heat eventually. It's more from the inefficient one because it needs more power.

Well, now I am curious, have you got any links that explain further? I will search on my own too.

Edit: http://www.eia.doe.gov/kids/energyfacts/sc...msofenergy.html

According to this page moving electrons is work, so energy is applied and electrons are moved, there isn't any "heat", except that from resistance to electron flow.


I lol'ed so hard because Tor's informative learning is fun explanation of what energy is, does sound a little like nubie's Energy Kid's page, but nobody else seems to be getting the joke. If it was intentional. :lol:

What he is saying makes sense if you realize he is sort of talking about entropy. Entropy is a function of a quantity of heat which shows the possibility of conversion of that heat into work. But it is misleading because the earth is not a closed system. It is heated by the sun. Because entropy in a closed system will always increase... what any of this has to do with electronics that will last about 10 years I have no idea.

The relevant part of Tor's statement is that in Pandora's partly closed system energy only leaves as things like, sound, visible light from the LCD, and so on, but mostly as heat. But so what. Think of the battery expending all it's energy, but over the course of ten hours. You would not expect it to be much heat, Pandora is not some kind of stylish space heater.

What every one else is saying though is that Pandora would not over heat in the same way as you would not worry about calculator over heating.

 

[Squidge]

Maybe someone can write a program to set CPU clock preferences for different applications

Or maybe they can leave the CPU clock preferences alone, as this isn't a GP2X, it's a multitasking notebook with game controls