Computers Faster Only for 75 More Years? Physicists determine nature's limit to making faster processors
October 14, 2009 By Lauren Schenkman, Inside Science
Image credit: ZyMOS
With the speed of computers so regularly seeing dramatic increases in their processing speed, it seems that it shouldn't be too long before the machines become infinitely fast -- except they can't.
A pair of physicists has shown that computers have a speed limit as unbreakable as the speed of light. If processors continue to accelerate as they have in the past, we'll hit the wall of faster processing in less than a century.
Intel co-founder Gordon Moore predicted 40 years ago that manufacturers could double computing speed every two years or so by cramming ever-tinier transistors on a chip. His prediction became known as Moore's Law, and it has held true throughout the evolution of computers -- the fastest processor today beats out a ten-year-old competitor by a factor of about 30.
If components are to continue shrinking, physicists must eventually code bits of information onto ever smaller particles. Smaller means faster in the microelectronic world, but physicists Lev Levitin and Tommaso Toffoli at Boston University in Massachusetts, have slapped a speed limit on computing, no matter how small the components get.
"If we believe in Moore's laW ... then it would take about 75 to 80 years to achieve this quantum limit," Levitin said.
"No system can overcome that limit. It doesn't depend on the physical nature of the system or how it's implemented, what algorithm you use for computation … any choice of hardware and software," Levitin said. "This bound poses an absolute law of nature, just like the speed of light."
Scott Aaronson, an assistant professor of electrical engineering and computer science at the Massachusetts Institute of Technology in Cambridge, thought Levitin's estimate of 75 years extremely optimistic.
Moore's Law, he said, probably won't hold for more than 20 years.
In the early 1980s, Levitin singled out a quantum elementary operation, the most basic task a quantum computer could carry out. In a paper published today in the journal Physical Review Letters, Levitin and Toffoli present an equation for the minimum sliver of time it takes for this elementary operation to occur. This establishes the speed limit for all possible computers.
Using their equation, Levitin and Toffoli calculated that, for every unit of energy, a perfect quantum computer spits out ten quadrillion more operations each second than today's fastest processors.
"It's very important to try to establish a fundamental limit -- how far we can go using these resources," Levitin explained.
The physicists pointed out that technological barriers might slow down Moore's law as we approach this limit. Quantum computers, unlike electrical ones, can't handle "noise" -- a kink in a wire or a change in temperature can cause havoc. Overcoming this weakness to make quantum computing a reality will take time and more research.
As computer components are packed tighter and tighter together, companies are finding that the newer processors are getting hotter sooner than they are getting faster. Hence the recent trend in duo and quad-core processing; rather than build faster processors, manufacturers place them in tandem to keep the heat levels tolerable while computing
speeds shoot up. Scientists who need to churn through vast numbers of calculations might one day turn to superconducting computers cooled to drastically frigid temperatures. But even with these clever tactics, Levitin and Toffoli said, there's no getting past the fundamental speed limit.
Aaronson called it beautiful that such a limit exists.
"From a theorist's perspective, it's good to know that fundamental limits are there, sort of an absolute ceiling," he said. "You may say it's disappointing that we can't build infinitely fast computers, but as a picture of the world, if you have a theory of physics allows for
infinitely fast computation, there could be a problem with that theory."
© Inside Science News Service, Used with permission.
May 09, 2006 |
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Now, all one needs is the speed of today's fastest processor. Parallel processors don't count, only individual, one instruction at a time, processors.
The funny thing is, that old Kaypro did office tasks just as fast as today's Excel and Word. I also have a 10-year old laptop with Windows-98 and Office-97. I actually prefer writing and calculating with it, since it is more responsive and feels faster than today's Win+Office on the latest laptops.
40 times doubling the performance would be unimaginable, yes. But I bet that the Windows and Office of the day will quite effortlessly waste enough horse power to make work even slower than today.
That stupid paperclip will probably be churning away rewriting your paper for you "Did you mean to say (40 pages rewritten)? Your intended audience will find my version 47% more understandable..."
Totally agree, developers were constrained by 2-3MHZ 8 bit CPUs + tiny amount of RAM, and the algorithms, written in pure assembler, had absolutely magic optimizations. Apply that kind of effort to current software, and you'll get desired 40 times gain in speed with the same hardware.
http://ftp.nada.k...Brains2/
011011100110000111010101001100001111001010101100 to the processor for example, we would just send the shade of green in one blip. There is a lot of room for speed. And there is a lot of other tricks we can use in the computer world.
So once again, THERE IS NO SUCH THING AS A SPEED LIMIT.
Can your old machine convert a movie between HD video formats in a matter of minutes (or at all)? Can it sort through and analyze data coming in at the rate of GB/s? Can it perform any of the functions that modern computers do OTHER than office tasks?
I thought not. You're seriously oversimplifying things, and I think you know it.
The old office tasks were much more constrained in terms of touchy-feely things like styles, colors, graphics and layout, productivity things like accessing data from other documents over (inter-) networks, etc. And dot-matrix printing was expensive, slow and ugly.
Now we have significant aesthetic and cost improvements: [Ooh, Aero! Pretty, pretty! Me want! Me want check my Facebook friends in separate tab during this boring YouTube video.]
But I think there are several orders of magnitude left before human demand for compute cycles is satiated.
[Now that we've past Uncanny Valley, me want faster WiMAX to experience 3D-HD roboporn with fully interactive brain implants & bodysuit, in back seat while robot drives.]
Maybe by that time, other, more autonomous robots will be smart enough to put us out of our misery.
At least that was what Isaac Asimov did with the Multivac at his short story THE LAST QUESTION.
HaHaHaha! That's Funny!
Seriously though, this article is kind of like the "Man will never fly" statement. Someone will figure out a way around that limit. No question about it in my mind.
2 Computers working at the speed of light. 1 using binary and using a more efficient form of communication. The binary one will be much much slower. It's not just about pure speed.
I really like the Asimov reference. Hopefully we can get there in my lifetime! (Although I doubt it. I think we'll end up in a 'state of the art & stone age' world at the same time, due to war, ultimately driven by religious bickering). Getting to the level you suggest would be amazing though. Asimov could have been right. Perhaps the big bang came about through science becoming ALMOST infinite in its processing capabilities.
""Anyway, 40 times doubling the current performance, it's unimaginable!" Yes. 25 years ago I was using a Kaypro-II, 0.002GHz 8-bit CPU, 0.000064 Gigs of RAM, and no hard drive."
You faced just 12 times doubling that performance, it is around us now.
40 times doubling that (25 years old) performance would be 2.2 EHz (ExaHertz or 2199023255 GHz). EM radiation wavelength at that (2.2 EHz) frequency is less then 0.14 nm. To compensate for those 25 years today, multiply this figure by 4096.
2^35 or 2^40 is such improvement that we never faced it since begining of computing.
By using trinary or quaternary bits in 3D DNA style arrangements, you would increase the processing power by a cubic factor, and reduce its size the same amount.
Its like someone in the 20's saying that waterships will never exceed 50-60 KPH because of cavitation around the propellor. Jet propulsion? Oh, gee I guess they didn't think of that when they confidently made their decree. Why? Because propellors were all they knew. Jet propulsion wasn't INVENTED yet.
Why must these people opine so convincingly when their thought processes are trapped in 2009. Tragic.
True. But consider this: when i was in elementary school (early sixties), we didn't have calculators, so to do a floating point multiplication on pencil and paper (with, say, a dozen digits of precision) took some three minutes, for non-engineers. Today my desktop does 7Gflops, which is a 2^40 improvement in speed!
At that time we could have said that "we never faced it since begining of computing", too. After all, never before had so many children had the ability to do that kind of arithmetic.
Nobody thought we'd see a 2^40 improvement in 40 years.
Imagine what seti@home &co could do another 40 years from now! All the worlds "unimaginable" hardware combined to solve some amazing task! (But, please, not "does God exist?")
Sure, sailing ships can't and never will be able to reach orbit no matter how many masts we build into them. But rocket ships can.
Todays computers = sailing ships
Tommorrows computers = ?.
Sure we can have unlimited powerful computers that are parallel, but they won't be fast. Their speed is limited.
If you actually read the article you will see that it is about Moores law, and not necessarily about the speed of light.
I was thinking the same thing after reading the article. It is like having a movie where there the conflict in the story has been edited out...