Core i7 2620M -- why dual core i7???

But where does the energy go after that?

All the energy that goes into the laptop through the power cord must come out. If it doesn't leave as heat, light from the screen, or noise from the fan, then where does it go?

 

We don't get 'free' computing power - that's where it goes. Some of that energy is actually used for doing what we intended/hoped it would do and not simply be converted to heat (like a light filament).

 

All energy consumed by electronics baring the screen (light), speakers (sound), HDD (noise) and fan (noise) is given off as heat.

The actual processing of data uses no energy, it does not consume energy as it were.

Since no useful mechanical work is done, nor light/sound released (apart from the exceptions above) then heat is the only way it comes out.

 

Energy cannot be created or destroyed. It doesn't disappear after it is used in a computer. It still has to go somewhere.

 

Exactly and there is no such thing as a "processing" energy that comes out of your computer.

In that case processed data would be at a higher energy state so every time you formatted your hard drive it would explode in a ball of flame.

 

My, you guys are really joking here, right?

How do you explain that a 35W part can do more 'work' than an older 130W part? (Part=cpu).

It is simply because it is more efficient at doing that work (i.e. more energy is expended to produce the work than to be simply converted to heat).

'Processing' is not energy. It is the desired outcome. But it takes energy to achieve.

Heat is the useless byproduct of a non-efficient method of getting that processing done.

 

If a computer is pulling say 100 watts from a power outlet, where is all that energy ending up? If the 100 watts of energy is entering the system, 100 watts of energy has to leave it unless it is accumulating energy. Every last bit has to be accounted for. The only ways for it to leave the computer are as light, sound, or heat.

 

Look your CPU is just a massive resistor. If you can get away with doing more while keeping that resistance low then you dont need to pump so much energy into it lol.

Processing power is just a byproduct lol. Electrically speaking.

For instance if processing power was a form of energy then setting up a resistor as a simple low pass filter would technically process any signal I put through it.

However I can measure all the losses in the circuit as simply a resistance, there is no more energy going elsewhere.

 

absolutely!

What you guys are forgetting is that the heat is a by product, a waste.

Do you guys remember from college that machines are rated by their efficiency? As in how much energy that I will put in there is going to be transformed in an usable work?

Say a 80% efficiency machine is going to pull 100w from the wall, so in that sense we all know how much energy the machine is going to dissipate, 80w.

The processing is actually done using the energy.

When a current passes in an analogue pulse, it gets a wave like format, however when its passed using a digital format, it gets a box format, lets say it ranges from 0 to 1 in the x axis. So now you understand why the pc uses binary.

The heat is a consequence of the inefficiency of the machine, not because its the end purpose of the energy itself. Heat is nothing but a sore thing for pcs as we all know.

So the conservation law still holds true.

 

Don't forget that electrical components emit heat (even if it isn't noticeable to you because it isn't dumping massive amounts of heat into a heat sink, it doesn't mean it isn't there), and energy waves ('visible' light waves -not always seen as it is sometimes in the IR/ UV spectrum, and that the component's casing keeps that 'within' the components- and in the form of Electrical Magnetic waves/ energy -such as wi-fi, and plain and simple EMF-), and noise (that light 'humm' you are hearing from your computer is created somehow, and there is high frequency sounds you can't hear), and don't forget the constant spinning of components (hdd, fan, DVD drive, ect... all the little motors are using energy)

And then what Mr MM said about the efficiency of the parts, and how the waste is it is all a byproduct

 

But the vast, VAST majority of it will be in the IR part of the spectrum (heat).

 

yes it will, but that dont mean again that TDP = power drawn

 

My thread's been fatally hijacked. :-(

Anyway, I still think Intel owes us an explanation as to why they have dual cores in their i7 category of processors. Makes more sense to keep all dual cores in the i5 or i3 realms, keep the top-end i7s as quads only. Plenty of wiggle room to define each of the several quads now in their corral. And they can always come up with some catchy marketing labels for the higher-end dual cores, like "Tweaked", "Super-Tweaked", "Tweaked Beyond Belief", or "This ain't your daddy's tweaked CPU". Something like that.

 

you have to remember the division

i3 - budget
i5 - mainstream
i7 - enthusiast

now its good for a company to have an i7 chip as an option on every model, so that someone can regard it as the pinnacle of power.

You also have to remember one of the causes for the hijacking, the TDP, dual core parts have a TDP of 35w while quad core 45w, so for slim models, quad cores are not an option, and since those same models are regarded as the premium line it makes more sense to have enthusiast chips as an option.

it wont make sense in desktops, since that its a completely different line of thinking.

think like an economist and you will get the drift

 

I think like an engineer, alas:

i3 = fast
i5 = faster
i7 = fastest

 

its the same principle, however in your measurements equal increments are expected or that someone would notice the difference in speed, mine doesnt.

 

i7 2620 has 4mb cache maybe thats why

 

so what are the uses for cache ?

 

Yes, I mentioned that above on this thread as the only discernible difference between this i7 chip and the line of i5 chips .... one extra megabyte of cache. It's supposed to help speed up processing.

 

But as an egineer if:

A = B + C and B >>> C

Then:

A = B

 

Oh god, no, please dont. Any engineer that is worth its penny knows something about numbers and that is too much

 

The scientest does everything the closest accuracy.

The engineer does it to the needed accuracy.

If I have a CPU that consumes 45W and 99.9% of its energy comes out as IR then saying it has a 45W thermal output is true.

Real world varations in power supply voltage and chip quality are going to dwarf the difference.

 

so how do you know that 99% of the energy is IR?

 

Engineering - this is where the semi-skilled workers realize the work of better minds. Hello, Oompah-Loompahs of science.

 

Sheldon Cooper

lol

 

Yeah he popped up in my mind when you guys where talking about engineering

YouTube - TBBT - Oompa-Loompas of Science

 

oops......

 

There are two problems I can think of with your explanation.

First is that you are not accounting for all the energy. You can say that a processor X% efficient all day long, but you are not saying how that X% of energy is leaving the computer. All the energy that goes in must come out one way or another.

Second is how can you define any outputs in terms of energy? How much energy is the answer to 48/2(9+3)? The output of the computer cannot be measured in units of energy, so you can't arrive at saying that a computer is using X% of its energy doing what you want and giving off Y% wasted as heat. With a lightbulb, engine, or bicycle, we can measure how much energy we are putting in, and how much usable energy we are getting out. You can't do that with a computer. It takes ALL the energy going into it to reach the desired output. You can make relative comparisons of efficiency though.

IR =/= heat output, it is just a part of it. Anything that is hot or warm is going to be releasing EM radiation, but that is usually very very minor. If you can feel warm air coming out of the exhaust, or that the case is warm, that is not IR radiation. However, I do agree with you that all the energy going into a processor will be emitted as heat. I just think that the vast majority of the energy going in will leave through convection and conduction.

Aside from the sound from the fans, optical, and hard drives, kinetic energy imparted to the air flowing through the case by the fan, and the light given off by any LED's and the screen (all these things make up a small minority), all the energy is leaving as heat due to electrical resistance.

 

Science without practical application is pointless.

And actually figuring out how to use it can be the hard and useful part.

 

lost it at least have fun with it

 

I'm sorry but I have no idea what that means.

 

Hey guys - so trying to get back to the thread title.

Personally choosing between these CPUs on the X220. I would normally do the i5, but for USB3.0 and that my budget will cover the i7 (yay discount coupons). Is there any reason that the i7 seems to be scoring lower than the i5 in the benchmarks I've seen
PassMark Intel vs AMD CPU Benchmarks - High End

 

yes, SSDs, or other system changes, we dont have info on the system itself

 

i also have an interest in this matter. i want to find out why it seems that the i7 2620M is eating up more power than an i5 2410M both in light use. Its theoretically absurd...







On another matter as much as i like sheldon cooper in real life there are 2 (to say the least) kinds of engineers
-brilliant
-average

and as much fun as it is to dwell in theory all day long, there is also 2 kinds of scientists (as if engineers are not scientists, but well, i think you get it)
-genius
-average

now a genius can advance humanity greatly but average are somewhat meaningless. while brilliant also can advance in good measures, average eng's mostly do stuff without much meaning but often some do find gold either just by chance or a genius moment.
so if you do the math, more engineers have changed the world than scientists did.