Power consumption is the major limiting factor for next generation computing systems, says Craig Hampel. Rambus has made its name in the development of memory sub-systems and is working with Microsoft on new low temperature memory technologies, says its chief scientist. This can lead to higher performance, lower power and extend Moore’s Law for up to a decade.
“As you decrease the temp and increase the compute density the enemy is thermal noise and self induced voltage-based noise, so temperature is the free variable,” he said. H epoints to Microsoft putting datacentres into the sea as the first step in reducing the temperature.
"You have datacentres now in the sea, and that’s impressive. The next point is cryogenics, and here liquid nitrogen is extremely cost effective so that’s where some of our work is at 77K and CMOS and RAM has interesting properties at that temperature. There’s a 4 to 8x improvement in energy efficiency - usually leakage current prevents lower voltages but we think at 77 K we can get threshold voltages down to 0.4 to 0.6V and the leakage goes away so you get 4 to 8 years of Moore’s law scaling,” he said.
“The next place that you get even more radical power and computational scaling is a 4k with superconductors so we use 77K as a step to true superconducting and we are working with Microsoft on superconducting processors – perhaps with the memory subsystems at 77K. The extreme on that curve is quantum computers and these tend to be in the millikelvin range – we view thermal improvements as an enabler to extending computational density for the next 20 years or so.”