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Samsung '3D' Memory Coming, 50% Denser
CWmike writes "Samsung on Tuesday announced a new 8GB dual inline memory module (DIMM) that stacks memory chips on top of each other, which increases the density of the memory by 50% compared with conventional DIMM technology. Samsung's new registered or buffered (RDIMM) product is based on its current Green DDR3 DRAM and 40 nanometer (nm)-sized circuitry. The new memory module is aimed at the server and enterprise storage markets. The three-dimensional (3D) chip stacking process is referred to in the memory industry as Through Silicon Via (TSV). Samsung said the TSV process saves up to 40% of the power consumed by a conventional RDIMM. Using the TSV technology will greatly improve chip density in next-generation server systems, Samsung said, making it attractive for high-density, high-performance systems."
Core memory is static in the true sense of the word. I've got core memory that hasn't changed a bit in 60 years. Punks !! You don't know memory.
Googling a bit, one test showed 2x1 GB of memory consuming up to 7.28 watts.
http://www.tomshardware.com/reviews/hardware-components,1685-13.html
For PC, that's practically nothing. For mobile devices, every watt counts.
Not just mobile. Newer generations of HTPCs, Plug like devices are using 20W. The AppleTV2 has a 6W power supply. Assume they overspec'ed it by 20%, that's 5W at full tilt.
7W is a huge % of those numbers.
Not just mobile. Newer generations of HTPCs, Plug like devices are using 20W.
Yeah, I measured my MythTV frontend at 26W from the wall; so if the 4GB of RAM is taking 14W, that would be more than half the total consumption of the entire system.
We've added another dimension, and got 50% denser. Sounds like we didn't do our jobs very well.
Additionally, an average server has 2x cpus, 8x memory, while having 0x graphics compared to an average desktop. Another problem is that we are running out of tricks for reducing dram power, which means that the portion of dram power may increase steadily in the near future.
Even graphic cards have a sizable, high-bandwidth ram on-board.
Trust me, DRAM power consumption is becoming a serious probpem.
3D geometries have serious issues with line saturation and heat dissipation. This is because of thermal noise, and the increased voltage needed to overcome it. (which in turn, creates more heat.)
We are already at the point where high performance RAM chips need heat spreaders, and that is with 2D chip geometries that can eliminate heat reasonably efficiently.
When you start stacking multiple silicon fab layers together, heat builds up in the layers, requiring more voltage to overcome thermal noise, which produces more heat...... You get the idea.
Without separating the layers with some kind of highly thermally conductive intermediate to pipe the heat out, the insides of the chips become little easy bake ovens, and estimated service life drops radically, as does performance metrics.
I could see them going 2 levels deep in the geometry, with a special package with heat spreaders on both sides (of the package itself that is- not the DIMM) or something crazy like that-- but I really can't see a big "solid 3D block" of silicon getting plugged anywhere. IF such a technology were to come into being, it would need to be made from something that is damned near to being a room temperature superconductor to keep from being unreliable/a fire hazard from thermal noise.
Alternatively, it could be done in a photonic computing approach, using optical transistors and optical interconnects... that would solve the heat problem too, but would make servicing the system substantially more difficult.