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Why Do Computers Use So Much Energy?

blogs.scientificamerican.com

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Re: Why Do Computers Use So Much Energy?

#61

Post by old-gregg »

flyGuyOnTheSly wrote: post #54
lucideer wrote: post #12

> Precise estimates vary, but currently about 5 percent of all energy consumption in the U.S. goes just to running computers 30% goes on transport. > the human brain is a computer. This particular computer uses some 10–20 percent of all the calories that a human consumes So society's computer uses 5 percent and our own, evolved over millions of years, uses up to 20. I'm not saying computers can't or shouldn't be made…

My thoughts exactly. When reading the title I thought "They do?" My laptop consumes the equivalent of approximately a single 60w incandescent lightbulb that used to be required just to write on a pad of paper in the dark. It's capable of quite a bit more than that, however. EDIT: Updated power specifications to exact amounts.

Your laptop consumes 200w? Maybe I'm not reading this right, but I have a modern 3.5Ghz/8-core server in the closet which runs a small army of VMs and its from-the-wall draw never exceeds 80w (about 35w on idle).

Re: Why Do Computers Use So Much Energy?

#64

Post by SilasX »

lucideer wrote: post #12

> Precise estimates vary, but currently about 5 percent of all energy consumption in the U.S. goes just to running computers 30% goes on transport. > the human brain is a computer. This particular computer uses some 10–20 percent of all the calories that a human consumes So society's computer uses 5 percent and our own, evolved over millions of years, uses up to 20. I'm not saying computers can't or shouldn't be made…

Did anyone click the link? It's comparing to the theoretical limits and the potential of minimal-energy reversible computing[1].

When you talk about "computers using so much energy", the span of inefficiencies could include:

A) Why so much energy per primitive operation (e.g. write bit to data store, XOR two registers)?

B) Why so many primitive operations per desired computation task (sum these three numbers, find the largest of these five numbers)?

C) Why so many computation tasks per unit of economic value delivered?

The article is talking about A). I'm pretty sure we've improved on A) over the history of computation.

I think we've gotten worse on B) per Metcalfe's law (Intel giveth and Gates taketh away).

[1] Called "reversible" because thermodynamics says the only reason you need to dissipate heat/usable energy is because you perform an irreversible operation, and to avoid that you'd have to do your computations using only reversible logical operations -- where the input space has a one-to-one mapping to the output space.

Re: Why Do Computers Use So Much Energy?

#65

Post by flyGuyOnTheSly »

old-gregg wrote: post #61
flyGuyOnTheSly wrote: post #54

Earlier quoted context omitted.

My thoughts exactly. When reading the title I thought "They do?" My laptop consumes the equivalent of approximately a single 60w incandescent lightbulb that used to be required just to write on a pad of paper in the dark. It's capable of quite a bit more than that, however. EDIT: Updated power specifications to exact amounts.

Your laptop consumes 200w? Maybe I'm not reading this right, but I have a modern 3.5Ghz/8-core server in the closet which runs a small army of VMs and its from-the-wall draw never exceeds 80w (about 35w on idle).

My laptop is far from modern. It also has to power an old screen.

Re: Why Do Computers Use So Much Energy?

#66

Post by orev »

flyGuyOnTheSly wrote: post #54
lucideer wrote: post #12

> Precise estimates vary, but currently about 5 percent of all energy consumption in the U.S. goes just to running computers 30% goes on transport. > the human brain is a computer. This particular computer uses some 10–20 percent of all the calories that a human consumes So society's computer uses 5 percent and our own, evolved over millions of years, uses up to 20. I'm not saying computers can't or shouldn't be made…

My thoughts exactly. When reading the title I thought "They do?" My laptop consumes the equivalent of approximately a single 60w incandescent lightbulb that used to be required just to write on a pad of paper in the dark. It's capable of quite a bit more than that, however. EDIT: Updated power specifications to exact amounts.

If your laptop consumed that much power it would be too hot to use on your lap and also would probably damage whatever surface you put it on. Just because a power supply has a max rating of X Watts doesn’t mean it’s always using that much. Even then, 200w for a laptop is an enormous amount. Maybe you meant LED bulbs that emit the equivalent light of a 100w bulb? That would be much closer to standard laptop power consumption.

Re: Why Do Computers Use So Much Energy?

#67

Post by usrusr »

visarga wrote: post #48
justtopost wrote: post #43

Earlier quoted context omitted.

What about bacteria? Unfortunately weighing the value of life is hard. As cute as kittens, and spiders, daffidls and protozoa are, we aren't equal. And evolution did not 'make humans', and we are not the intended product of the big bang. Seems the ultimate hubris to bill the total energy expended by the universe so far to the creation of us forum posting meatbags.

There would be no forum posting meatbags if not for evolution and its enormous resource usage. While I agree that nature did not 'intend' to make humans from the beginning, we, as humans, can't just write it off. Those bacteria are an important step in our cellular apparatus, and people are comparing computers to brains (brain cells at work), here. And as long as we can't get our energy without killing other living o…

> And as long as we can't get our energy without killing other living organisms

It is perfectly possible to fuel a human only from biological sources that have died a natural death. It's exactly the same as running a computer on fossil fuels, just without the millennia of waiting for sufficient accumulation that you need for building a whole industrial base in one short flash in the pan moment (compared to the millennia of accumulation).

Actually, you don't even have to wait for organisms to die, you can even use fuels where the providing organisms live on, having just shed off a part they don't need anymore. No killing involved in eating an apple. And if you plant the seeds in an advantageous environment you are even taking an active role in their procreation, as the seeds that just drop into the shade of the parent tree won't thrive there.

Re: Why Do Computers Use So Much Energy?

#68

Post by C1sc0cat »

pjc50 wrote: post #3
pizzakiller85 wrote: post #2

What i don't understand is how a phone can be so powerful with so little watt usage. especially compared to a PC

There's a lot less of it, and PCs aren't nearly as optimised for low energy usage.

They are compared to the amount of work they can do per watt when compared to the original IBM PC.

Old school mainframe power suplies are probably even less efficient per what.

Re: Why Do Computers Use So Much Energy?

#69

Post by oatmealsnap »

flyGuyOnTheSly wrote: post #65
old-gregg wrote: post #61

Earlier quoted context omitted.

Your laptop consumes 200w? Maybe I'm not reading this right, but I have a modern 3.5Ghz/8-core server in the closet which runs a small army of VMs and its from-the-wall draw never exceeds 80w (about 35w on idle).

My laptop is far from modern. It also has to power an old screen.

200W still seems really high. A +10yo MacBook Pro used an 85W charger, and it rarely if ever reached that max. I find it hard to believe that even an old gaming laptop would require over twice that.

Re: Why Do Computers Use So Much Energy?

#70

Post by [deleted] »

lucideer wrote: post #12

> Precise estimates vary, but currently about 5 percent of all energy consumption in the U.S. goes just to running computers 30% goes on transport. > the human brain is a computer. This particular computer uses some 10–20 percent of all the calories that a human consumes So society's computer uses 5 percent and our own, evolved over millions of years, uses up to 20. I'm not saying computers can't or shouldn't be made…

[deleted]
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