Con:
Someone else holds the patents on bus A.
Pro: bus type B's patents have expired...
Although today's processors are all residents of Flatland, AMD's head chippery honcho says that multi-level, multi-core processors may be the wave of the future. "I'm not saying it's an easy dimension, the third dimension," AMD's senior vice president and headman of the company's Technology Group Chekib Akrout cautioned The …
..... into Affirmative Creative Reaction in HyperRadioProActive IT Fields and a Beta Reality for All.
"Oh, well. We're going Z. The amazing progress of the last 30 years is not even close to ending. Frankly, it's a relief." .... Mikel Posted Thursday 11th November 2010 22:04 GMT
I would agree, Mikel, and boldly go even further and state that even greater amazing progress and processing for programming is only just starting .......
And as for ..."I lost count of how many people called me crazy when I suggested such a thing many years ago." ...... :-), well, who would be the crazy fools now then, Mikel, and who would be the wiser sage?
"lower thermal charachteristics could act as a sort of insulator between two toasty cores"
So just how is putting a thermally insulating layer between two hot cores going to assist with removing heat from them? It's surely going to make the problem worse.
The subject of 3D semiconductor fabrication regularly reappears over the years, but we've yet to see much come of it. The issues of fabrication, cooling and design are incredibly difficult.
Peltier coolers are just semiconductors, so why not use a layer of Peltier elements to shove heat either to the edges of a chip (so it can be disposed of) or to the colder parts of the chip (removing any huge thermal gradients)?
Not Anon so AMD know where to send the consultancy fee.
Is silicon worse than the heat sink? Aluminium is 1.59 times more thermally conductive than silicon. Gold is 2.13 times more conductive, and copper is 2.69 times more conductive than silicon.
A big difference, but not an order of magnitude. A lower power dissipation processor like the ARM is going to be much easier to do 3D stacking with, like stacked on edge. Yet another reason why ARM have Intel running scared.
Yes I know we use heat pipes these days, but we use such exotic methods because the Intel x86 architecture is so ridiculously inefficient.
All but low power chips would probably have to have embedded liquid/gas heat pipes, and possibly heat conductive materials to feed heat to the heat pipes, between the layers. The heat pipes would need to use a non 'furring' coolant and the chip would either need coolant ports or have a decent heat sink interface.
Some potential problem are:
1. having fast enough heat flow to stop any layer from overheating
2. preventing chip fracture from excessive pressure, vibration. turbulence or heat shock, if external coolant is pumped through the chips.