*

Offline Rushy

  • Planar Moderator
  • *****
  • Posts: 8119
    • View Profile
Re: Ordered a new computer
« Reply #80 on: April 27, 2018, 04:06:42 PM »
Heat pipes are relatively new technology

*

Offline Lord Dave

  • *
  • Posts: 7043
  • Grumpy old man.
    • View Profile
Re: Ordered a new computer
« Reply #81 on: April 27, 2018, 04:20:35 PM »
It sounds like y'all are arguing over different parts of the same thing.

Parsifal, Pete, and Rushy sound like they're saying "TDP is electrical power that's being converted to heat" which is accurate.  The CPU won't generate any watts of heat without electrical power and it will need to draw at least the amount of power needed to produce the heat it outputs.

Thork is saying that the CPU is pulling more than the heat generated (which is also true), but where he's wrong is the energy it's pulling isn't stored in the CPU.  It just passes through.  Like, unless I'm mistaken, a CPU isn't going to store a charge inside itself then release that charge to the motherboard to send a signal to read RAM.  It'll simply have a path of electrical charge that leads from the motherboard's BUS through the CPU and out to the RAM.

I would personally ony count the electrical power the CPU uses for computation within itself, not what essentially passes through after a calculation.

Of course, having almost no background in microprocessor architecture and engineering, I could be wrong about the above.
If you are going to DebOOonK an expert then you have to at least provide a source with credentials of equal or greater relevance. Even then, it merely shows that some experts disagree with each other.

*

Offline Dr David Thork

  • *
  • Posts: 5180
  • https://onlyfans.com/thork
    • View Profile
Re: Ordered a new computer
« Reply #82 on: April 27, 2018, 04:30:22 PM »
@Parsifal I told you that about half of the power going in comes out as heat.

You asked, where does the rest go.

I gave you a bunch of possible places including communication, losses and mechanical work of physically moving the transistors which have a mechanical resistance, not all of which becomes heat.

Why is this hard to understand? You know you can't put 100% electrical energy in and get 100% heat out. There will be a difference between those two numbers.

 Power draw (watts) = work done (watts) + other losses (watts) + heat losses TDP (watts).

You know TDP can't be power draw.

Also some of your objections are weird for a scientifically minded person.
Well, some of the power is passed on to other components.

This is negligible, since the purpose of these signals is to transmit information and not power, so there isn't a lot of current involved. But more importantly, this will just be turned into waste heat when it reaches those components anyway, so it makes no difference to the total heat the system generates.
Well CPUs do send 12v communications to some components so ... but mostly if the energy arrives at the RAM stick and loses heat there, that's not part of the TDP ... the heat coming off the processor die. You know that. That's heat elsewhere.

Some is lost to electro-magnetic radiation.

Which is a form of heat, albeit not one that needs to be extracted by a cooling system.
No, that's generating a magnetic field which causes resistance of its own as it permeates materials such as your copper heatsink. Pushing something metallic into a magnetic field uses energy. Like wise pushing a field out through metals must therefore also use energy because of newton's second law. Sure some heat, but not all heat. Some is going to be left hand rule force in Newtons.

Some is noise, you can hear a CPU.

Not over a 10W speaker. Also negligible.
Its all negligible. it takes 80,000 watts to power a Nissan Leaf. you are asking me where just 67 watts goes. The average human fart produces around 60 watts of power.

Some is vibration. If a CPU operates at 4GHz ... that's a lot of very shallow amplitude but high frequency oscillation. Imperceptible to you as a human, but guzzling power all the same.

4 GHz waves cannot permeate effectively in air. A 4 GHz sound wave in air has a wavelength of about 80 nm, which is short enough that it spans about 20 nitrogen molecules. You're playing pool with molecules at this point. This means the vibrations are never going to leave the computer, and therefore do not qualify as a form of loss.

Guess what happens to vibrations when they impart energy but don't travel very far as waves. Go on, you can think about this one for a bit.
That pool of moelcules is still being moved around. That's a loss. Billions of transistors, all moving gates, shifting molecules millions of times a second, it adds up.

Electrostatic losses when not all power send to capacitors/transistors reaches them.

Another form of heat...
No. That isn't heat. That's electrons that were stuck to something sodding off and having to be replaced by new electrons. Bit like a balloon you rubbed on your head losing its charge after a while.

These days even quantum tunneling is a loss. Not all your electrons do the thing they were sent to do.

"These days"? Are you aware that quantum tunneling didn't just spawn into existence when it was discovered?

Nevertheless, this is both negligible and irrelevant, since electrons are matter and not energy.
Yes these days as the gates are only 14nm and the electrons can tunnel the gap. Much less a problem at 80nm gates. Its a problem that will only get worse as transistor sizes get smaller.

There are loads. A CPU isn't just made to generate heat.

Actually, that is literally what a CPU is designed to do. It's an entropy machine.
No. No, consider how silly that is. It is a counting machine. It happens like all machines to have losses.

Are you familiar with the Second Law of Thermodynamics? It states that the total entropy of a closed system must always increase. Now consider what a computer is supposed to do. The job of a computer is to take disorganised data -- with high entropy -- and turn it into a form that can be easily accessed by humans -- with low entropy.

Now we have a problem. To do its job, a computer needs to reduce the total entropy in its memory banks. Since the entropy in a closed system cannot decrease, this means that the computer cannot be a closed system, and it must generate more entropy than it removes. The more entropy it generates, the better it performs.

This is the technical reason for the common sense correlation between higher TDP and better performance. When it comes to computers, better performance is more waste heat.
No. I can take a 65W TDP processor and have 8 cores like the Ryzen 1700. I can also take a 65W TDP processor like the ryzen 1400. The former performs better because it has more cores. Not because it has a higher TDP. They have the same TDP. I could take a 7th gen i5 and give it hyperthreading. Still the same TDP but it will perform better.

TDP is the amount of heat it will throw off. Not the power draw. Why is this hard? A hyper threaded i7 guzzles a lot more than a non-threaded i5. They still have the same TDP. they don't have the same power draw or the same performance. The i7 does more work. It needs more power. But its heat loss is comparable because the energy from power draw is used in other ways. It is more efficient, hence the reason it performs better and Intel want another $100 out of you for the privilege.

It sounds like y'all are arguing over different parts of the same thing.

Parsifal, Pete, and Rushy sound like they're saying "TDP is electrical power that's being converted to heat" which is accurate.  The CPU won't generate any watts of heat without electrical power and it will need to draw at least the amount of power needed to produce the heat it outputs.

Thork is saying that the CPU is pulling more than the heat generated (which is also true), but where he's wrong is the energy it's pulling isn't stored in the CPU.  It just passes through.  Like, unless I'm mistaken, a CPU isn't going to store a charge inside itself then release that charge to the motherboard to send a signal to read RAM.  It'll simply have a path of electrical charge that leads from the motherboard's BUS through the CPU and out to the RAM.

I would personally ony count the electrical power the CPU uses for computation within itself, not what essentially passes through after a calculation.

Of course, having almost no background in microprocessor architecture and engineering, I could be wrong about the above.
The point is, not all the power drawn in, comes out as heat. Its very simple. So TDP is a lower number than power draw. Your chip always pulls more power than it expels in heat. Kinda obvious. Heat is a loss. The chip is doing useful work as well.

total power = useful work - losses (of which one loss is TDP and must therefore be a lower number than total power drawn)
« Last Edit: April 27, 2018, 04:35:46 PM by Baby Thork »
Rate this post.      👍 6     👎 1

*

Offline Rushy

  • Planar Moderator
  • *****
  • Posts: 8119
    • View Profile
Re: Ordered a new computer
« Reply #83 on: April 27, 2018, 04:41:36 PM »
« Last Edit: April 27, 2018, 04:43:07 PM by Rushy »

*

Offline Dr David Thork

  • *
  • Posts: 5180
  • https://onlyfans.com/thork
    • View Profile
Re: Ordered a new computer
« Reply #84 on: April 27, 2018, 04:45:18 PM »
Like, unless I'm mistaken, a CPU isn't going to store a charge inside itself then release that charge to the motherboard to send a signal to read RAM.  It'll simply have a path of electrical charge that leads from the motherboard's BUS through the CPU and out to the RAM.
Yeah, you are mistaken. That's exactly how a CPU works. They have capacitors that store electrical energy and then release it on demand. Its not all transistors in a CPU. You need diodes, capacitors and resistors to make all the various types of logic gates.
Rate this post.      👍 6     👎 1

*

Offline junker

  • Planar Moderator
  • *****
  • Posts: 9920
    • View Profile
Re: Ordered a new computer
« Reply #85 on: April 27, 2018, 04:51:48 PM »
Holy goddamn this thread.

*

Offline Lord Dave

  • *
  • Posts: 7043
  • Grumpy old man.
    • View Profile
Re: Ordered a new computer
« Reply #86 on: April 27, 2018, 05:01:07 PM »
Like, unless I'm mistaken, a CPU isn't going to store a charge inside itself then release that charge to the motherboard to send a signal to read RAM.  It'll simply have a path of electrical charge that leads from the motherboard's BUS through the CPU and out to the RAM.
Yeah, you are mistaken. That's exactly how a CPU works. They have capacitors that store electrical energy and then release it on demand. Its not all transistors in a CPU. You need diodes, capacitors and resistors to make all the various types of logic gates.

So a logic gate will output a pre-stored charge on the output? Why wouldn't it just use the input signals?  Unless it's a NOT and needs to output from nothing to something.
If you are going to DebOOonK an expert then you have to at least provide a source with credentials of equal or greater relevance. Even then, it merely shows that some experts disagree with each other.

*

Offline Lord Dave

  • *
  • Posts: 7043
  • Grumpy old man.
    • View Profile
Re: Ordered a new computer
« Reply #87 on: April 27, 2018, 05:01:26 PM »
Holy goddamn this thread.
Hey, I'm learning a lot.  I'm happy.
If you are going to DebOOonK an expert then you have to at least provide a source with credentials of equal or greater relevance. Even then, it merely shows that some experts disagree with each other.

*

Offline Dr David Thork

  • *
  • Posts: 5180
  • https://onlyfans.com/thork
    • View Profile
Re: Ordered a new computer
« Reply #88 on: April 27, 2018, 05:03:36 PM »
So a logic gate will output a pre-stored charge on the output? Why wouldn't it just use the input signals?  Unless it's a NOT and needs to output from nothing to something.
Because it might be waiting for something else to complete a calculation, and it needs to put that info somewhere.
Rate this post.      👍 6     👎 1

*

Offline Rushy

  • Planar Moderator
  • *****
  • Posts: 8119
    • View Profile
Re: Ordered a new computer
« Reply #89 on: April 27, 2018, 05:04:24 PM »
Holy goddamn this thread.
Hey, I'm learning a lot.  I'm happy.

You're learning a lot of extremely wrong things.

*

Offline Dr David Thork

  • *
  • Posts: 5180
  • https://onlyfans.com/thork
    • View Profile
Re: Ordered a new computer
« Reply #90 on: April 27, 2018, 05:05:43 PM »
Holy goddamn this thread.
Hey, I'm learning a lot.  I'm happy.

You're learning a lot of extremely wrong things.
Well stop posting wrong things and make it easier for him.
Rate this post.      👍 6     👎 1

*

Offline Lord Dave

  • *
  • Posts: 7043
  • Grumpy old man.
    • View Profile
Re: Ordered a new computer
« Reply #91 on: April 27, 2018, 06:27:07 PM »
While I'm gonna side with Thork that the electrical energy used must be more than the wattage of heat being outputted (based on what I'm reading) I'm also gonna not suggest the total energy it draws is somehow double that.
If you are going to DebOOonK an expert then you have to at least provide a source with credentials of equal or greater relevance. Even then, it merely shows that some experts disagree with each other.

Re: Ordered a new computer
« Reply #92 on: April 27, 2018, 06:45:10 PM »
While I'm gonna side with Thork that the electrical energy used must be more than the wattage of heat being outputted (based on what I'm reading) I'm also gonna not suggest the total energy it draws is somehow double that.

Reading this thread or some outside source?

Just seems a quick way to disagree with everyone in one go.

Devils Advocate

Re: Ordered a new computer
« Reply #93 on: April 27, 2018, 10:52:32 PM »
NERD FiGHT!!!!!

JohnAdams1145

Re: Ordered a new computer
« Reply #94 on: April 29, 2018, 10:14:46 AM »
Baby Thork,

You are wrong here. Nearly 100% of the energy that goes into a computer is released as heat eventually (in a short timeframe, like a day). The CPU's TDP is a measure of essentially how much energy it turns into heat. Sure, there's a little bit that's transferred around the motherboard for signalling, but mind you, these communication lines have relatively high impedances compared to a power supply; probably no more than a quarter of a watt goes into signalling. Why? Well, it turns out that such energy would be used for ... heating other components, particularly in sensitive areas. There's just no need for any signalling pathway to use a lot of energy.

Switching transistors does not store useful energy. Switching losses happen because there is a voltage across the source and drain (or collector and emitter with bipolar transistors) when the gate (base) is driven on/off. During the switching delay, current leaks across a voltage drop. Transistors also have leakage losses. All of these losses turn to heat. This is why CPUs need lots of energy.

DRAM stands for dynamic random access memory. Why is it called dynamic? Because it needs to be "refreshed" as its capacitors leak current. That leakage current obviously doesn't go toward charging batteries (otherwise you could decrease the refresh rate by ditching the batteries). It goes to heat.

As for outside signalling, the energy use is minimal, and those devices primarily convert energy to heat as well. The one exception is if you decide to use your computer ports that contain supply rails to charge batteries. Yeah, I haven't seen that in common use.

Another way to look at a computer is to find all of the places it can store energy:
1. Capacitors (very small amount of energy)
2. RTC battery
3. Extremely small magnetic fields (and these will re-release the energy as soon as the computer is turned off).

The rest of the energy must go somewhere, and the only place for it to go is heat.

And you are wrong about CPU capacitors. They store minimal energy. Even the best capacitors today in terms of energy density store little compared to batteries, and the ones in the CPU are not made for energy storage. We are talking about micro/nanojoules that they can store.

Most of the CPU is transistor-transistor logic, so it is indeed mostly transistors. From transistors, gates are built. Then we use an HDL to describe electronic circuits, which is then synthesized into transistor layout.


The TDP quoted in the CPU manual is lower than power draw because of inefficiencies in the power supply and use in other parts of the computer (GPUs, spinning hard drives, lasers), which convert the electrical energy to -you guessed it- heat. If we sum up the power dissipation for all of the components and factor in the inefficiency of the power supply, we get essentially how much power is drawn.

The main takeaway is computers are essentially heaters that perform useful computation. They are, however, far less efficient than your air conditioner at heating.
« Last Edit: April 29, 2018, 10:25:54 AM by JohnAdams1145 »

*

Offline Dr David Thork

  • *
  • Posts: 5180
  • https://onlyfans.com/thork
    • View Profile
Re: Ordered a new computer
« Reply #95 on: April 29, 2018, 04:12:25 PM »
There are a number of reasons why this cannot be.

The first is that electricity runs on a circuit. And to do that, some of the electrons have to make their way around the circuit AND BACK TO POWER SUPPLY. Not all of the energy drawn by a CPU is used. Much returns to the power supply. Otherwise you only need one wire to make a circuit, not two. That is energy dissipated not as heat on the die.

So electrical watts in, already doesn't equal watts of heat out.

Next is Landauer's principle stating that electrical energy used is proportional to ln2 of the heat energy out. Not 1:1.
https://en.wikipedia.org/wiki/Landauer%27s_principle

Next is assuming the transistor contains all the resistance in the circuit, and therefore it should have to dissipate all the power in that circuit. But that is not the case.

Take a simple one transistor switch for example, make Vcc 12 Volts and the load resistor 10 ohms, now assume you want 100 watts from the load (it could be a light globe a motor or inputs to other transistors.

So you need to have 10 volts across the load resistor, you have 12 Volts as VCC, so the transistor (collector/emitter) from one let of a two resistor voltage divider.

So you have 10 volts across the load resistor, and 2volts across the transistor, but still only 10 amps into the load.

The transistor is only dropping 2 volts, (not 10 volts) (12volts - 2 Volts = 10 volts). But the transistor is dissipating 120 watts so 100watts goes into the load and 20 watts goes into heat in the transistor.

Now if the transistors collector/emitter resistance was the same as the load resistance, you would require a VCC of 20 volts and half the power would go to the load and half to the transistor.

The efficiency of a transistor is that it has a low on resistance and therefore low voltage (and power) consumption.

Finally assuming a processor is all transistors when 30% of its power used gets taken by the cache (a storage device) is semi-retarted. A processor has lots of parts, not just cores.



Also I think reducing the PCIe lanes to "probably no more than a quarter of a watt goes into signalling" is a reach.

TDP is Watts in joules and a guesstimate of how many heat watts you need to dissipate. Power draw is volts x amps to give you electrical watts required. The two are not the same.
« Last Edit: April 29, 2018, 04:26:41 PM by Baby Thork »
Rate this post.      👍 6     👎 1

*

Offline Rushy

  • Planar Moderator
  • *****
  • Posts: 8119
    • View Profile
Re: Ordered a new computer
« Reply #96 on: April 29, 2018, 04:24:46 PM »
TDP is Watts in joules and a guesstimate of how many heat watts you need to dissipate. Power draw is volts x amps to give you electrical watts required. The two are not the same.



*

Online xasop

  • Administrator
  • *****
  • Posts: 9275
  • Professional computer somebody
    • View Profile
Re: Ordered a new computer
« Reply #97 on: April 29, 2018, 04:25:12 PM »
Stop talking about electrons. When it comes to the behaviour of electrical energy in a circuit, the individual charge carriers are irrelevant. What you are saying is equivalent to claiming that pollution in rush hour doesn't happen because the cars go back home at the end of the day.

You obviously don't have the basic foundational knowledge required to understand how electricity works. I'm far from an expert myself, of course, but I'm amazed you can get an engineering degree with so little understanding of... well, anything. Please just stop before you sap what remains of everyone else's IQ.
when you try to mock anyone while also running the flat earth society. Lol

*

Offline Dr David Thork

  • *
  • Posts: 5180
  • https://onlyfans.com/thork
    • View Profile
Re: Ordered a new computer
« Reply #98 on: April 29, 2018, 04:29:59 PM »
Stop talking about electrons. When it comes to the behaviour of electrical energy in a circuit, the individual charge carriers are irrelevant. What you are saying is equivalent to claiming that pollution in rush hour doesn't happen because the cars go back home at the end of the day.
And you are claiming that all of the petrol goes into heating the engine and none of the energy does into driving you anywhere. You haven't even considered the kinetic energy of moving the switches.

This so unbelievably simple. Not all of a processors drawn power ends up as heat on the die. I think anyone with half a brain cell could work that out. There is no such thing as a perfect machine.
« Last Edit: April 29, 2018, 04:31:38 PM by Baby Thork »
Rate this post.      👍 6     👎 1

*

Online xasop

  • Administrator
  • *****
  • Posts: 9275
  • Professional computer somebody
    • View Profile
Re: Ordered a new computer
« Reply #99 on: April 29, 2018, 04:33:56 PM »
And you are claiming that all of the petrol goes into heating the engine and none of the energy does into driving you anywhere.

If the CPU's job was to impart kinetic energy unto the computer, this might be a valid analogy to make. Unfortunately for you, a CPU does a negligible amount of useful work, for the physical definition of "work".
when you try to mock anyone while also running the flat earth society. Lol