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Limits to Moore's Law Launch New Computing Quests
tringtring alerts us to news that the National Science Foundation has requested $20 million in funding to work on "Science and Engineering Beyond Moore's Law." The PC World article goes on to say that the effort "would fund academic research on technologies, including carbon nanotubes, quantum computing and massively multicore computers, that could improve and replace current transistor technology." tringtring notes that quantum computing has received funding on its own lately, and work on multicore chips has intensified the hunt for parallel programming. Also, improvements are still being made to current transistor mechanics.
It isn't a $20mil prize, it's a budget request.
No sig for you!!
Actually, transistors can also become more effective, and have been for decades. If not, you'd be right: Doublt computing-power would mean double power-consumption which would mean double heat-production and spell heaps of trouble.
We're still -far- away from the theoretical limits though.
Flipping a -single- bit MUST consume atleast kT joules, where T is the temperature in Kelvin and k is the Bolzmann-constant of around 10^-23.
So if your cpu runs at 300K (cooling it more won't help because then you'll spend energy for that) you can flip a physical max of sligthly over 10^20 bits. Run at 10Ghz, aproximately 10^10 Hz and you can flip a maximum of 10^10 bits every clock-cycle.
Current CPUs don't come anywhere close to being that efficient. They flip perhaps a million transistors in a clocktick which is a factor of 10000 less than they COULD be doing with a single watt, and they spend not ONE watt but more like 50W to do that.
Still, the limits are visible: We can, theoretically, up cpu-efficiency by a factor of 100.000, but a factor of a million looks, imho, physically impossible.
This sounds like a lot, but consider that if we keep doubling every 2 years, we'll hit the hard wall in 20 - 30 years. And long before we get close to the hard wall we'll be in a pretty steep terrain.
Unless we go with reversible computing in which case all bets are off and entirely new limits apply.