The Dark Silicon Problem and What It Means for CPU Designers (2013)
1–10 of 70 posts
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#2Why don't they start making CPUs 3 Dimensional like a cube with 6 "processors" each with multiple cores as its "sides" with the pins on the opposite sides of the cube wall. Seems to me more internal volume might allow for more cleaver head distribution channels
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#3Why don't they start making CPUs 3 Dimensional like a cube with 6 "processors" each with multiple cores as its "sides" with the pins on the opposite sides of the cube wall. Seems to me more internal volume might allow for more cleaver head distribution channels
If I understand correctly, neither heat dissipation nor existing manufacturing techniques are amenable to this approach. Also modern CPUs do have more than a dozen layers IIRC.
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#4Why don't they start making CPUs 3 Dimensional like a cube with 6 "processors" each with multiple cores as its "sides" with the pins on the opposite sides of the cube wall. Seems to me more internal volume might allow for more cleaver head distribution channels
less surface area per transistor makes the heat problem worse.
they are already a little bit 3d though.
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#5Why don't they start making CPUs 3 Dimensional like a cube with 6 "processors" each with multiple cores as its "sides" with the pins on the opposite sides of the cube wall. Seems to me more internal volume might allow for more cleaver head distribution channels
If I understand correctly, neither heat dissipation nor existing manufacturing techniques are amenable to this approach. Also modern CPUs do have more than a dozen layers IIRC.
I think op is talking about 6 flat normal chips as the sides. This would allow for cooling stuff inside the cube. Maybe having only 5 of the sides as chips would make it even easier to have a heat sink. The center of the cube could be copper or something.
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#6Why don't they start making CPUs 3 Dimensional like a cube with 6 "processors" each with multiple cores as its "sides" with the pins on the opposite sides of the cube wall. Seems to me more internal volume might allow for more cleaver head distribution channels
That still means multiple silicon dies, which we have known how to do for a while (see: Intel Core 2 Quad from 2006, and more recently AMD Epyc).
Having more dies lets you dissipate more heat, but then it's kinda hard to build low-latency / high-bandwidth interconnects between the dies. Inter-die buses go over a PCB or interposer, which impose higher parasitic capacitance and make it difficult/expensive to run wide interfaces. That's why techniques like "dark silicon" allocation are important - it allows us to get more perf in a single die.
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#7From the article
"The heat generation per unit area of an integrated circuit passed the surface of a 100-watt light bulb in the mid 1990s, and now is somewhere between the inside of a nuclear reactor and the surface of a star. "
I can't tell if this is hyperbole or not, it amazes me but no amount of googling is coming up with a useful answer. Is anyone able to confirm or deny it for me?
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#8We just need a clueless CIO to turn up and ask if 'Cloud' will solve the problem :D
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#9From the article "The heat generation per unit area of an integrated circuit passed the surface of a 100-watt light bulb in the mid 1990s, and now is somewhere between the inside of a nuclear reactor and the surface of a star. " I can't tell if this is hyperbole or not, it amazes me but no amount of googling is coming up with a useful answer. Is anyone able to confirm or deny it for me?
After a quick napkin calculation+google it seems the sun has around 20kW of power per square centimeter. So not entirely unfeasible that a cooler star, or a nuclear reactor is closer to the typical 10-100W/cm2 of a modern cpu/gpu. Still some orders of magnitude off from our closest star. (Hope calculation is correct)
Re: The Dark Silicon Problem and What It Means for CPU Designers (2013)
#10From the article "The heat generation per unit area of an integrated circuit passed the surface of a 100-watt light bulb in the mid 1990s, and now is somewhere between the inside of a nuclear reactor and the surface of a star. " I can't tell if this is hyperbole or not, it amazes me but no amount of googling is coming up with a useful answer. Is anyone able to confirm or deny it for me?
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