4 ms·

> 16 H200 GPU along with single digit TB HBM memory stitched together on a single substrate wafer How on earth would you cool this?

by verall 3y ago

MacsHeadroom 3y ago
Submersion cooling.
aleph_minus_one 3y ago
> How on earth would you cool this? With liquid nitrogen. :-)
snakeyjake 3y ago
Seymour Cray solved this problem 40 years ago. https://en.wikipedia.org/wiki/Cray-2#/media/File:Cray2.jpg https://en.wikipedia.org/wiki/Cray-2#/media/File:Cray2.jpg Bring back toxic waterfalls.
- shrx 3y ago
  The issue with Fluorinert is not toxicity but a very high global warming potential.
  - mensetmanusman 3y ago
    Fluorinerts with very low global warming potentials have been invented since then.
  - monetus 3y ago
    > Although Fluorinert was intended to be inert, the Lawrence Livermore National Laboratory discovered that the liquid cooling system of their Cray-2 supercomputers decomposed during extended service, producing some highly toxic perfluoroisobutene.[5] Catalytic scrubbers were installed to remove this contaminant. With that much constant heat, what chemical might be best/most practical I wonder. https://en.m.wikipedia.org/wiki/Novec_649 https://en.m.wikipedia.org/wiki/Novec_649 https://en.m.wikipedia.org/wiki/Hydrofluoroether https://en.m.wikipedia.org/wiki/Hydrofluoroether
jdietrich 3y ago
15kW dissipated over that area isn't particularly challenging for an industrial water cooler - within reason, you can just keep cranking up the flow rate. What'd scare me is power delivery, because they've probably got >10,000 amps going to the die. https://www.eetimes.com/powering-and-cooling-a-wafer-scale-die/ https://www.eetimes.com/powering-and-cooling-a-wafer-scale-d...
- buildbot 3y ago
  20K amps (!!!): https://vimeo.com/853557623 https://vimeo.com/853557623 They use probably the fanciest piece of rubber (and metal) ever made to pass the power in frontside to the die.
  - Dylan16807 3y ago
    Doing it with all that water needing to get everywhere is definitely a feat. But the power itself isn't too bad. A square millimeter of wire can comfortably carry 20 amps, and you can scale that up pretty straightforwardly. It looks like each of those 84 rectangles has to deal with 240 amps and has multiple square centimeters of contact with the voltage regulator card above it.
SAI_Peregrinus 3y ago
Direct-die vapor phase change cooler? That tends to be the fastest way to get heat out of a chip and to a big radiator. For industrial applications the need to run a big fan & a compressor are less problematic.
- deleted 3y ago
  [deleted]

> 16 H200 GPU along with single digit TB HBM memory stitched together on a single substrate wafer How on earth would you cool this?

by verall 3y ago

> 16 H200 GPU along with single digit TB HBM memory stitched together on a single substrate wafer How on earth would you cool this?

MacsHeadroom 3y ago

Submersion cooling.

aleph_minus_one 3y ago

> How on earth would you cool this? With liquid nitrogen. :-)

snakeyjake 3y ago

Seymour Cray solved this problem 40 years ago. https://en.wikipedia.org/wiki/Cray-2#/media/File:Cray2.jpg https://en.wikipedia.org/wiki/Cray-2#/media/File:Cray2.jpg Bring back toxic waterfalls.

shrx 3y ago
The issue with Fluorinert is not toxicity but a very high global warming potential.
- mensetmanusman 3y ago
  Fluorinerts with very low global warming potentials have been invented since then.
- monetus 3y ago
  > Although Fluorinert was intended to be inert, the Lawrence Livermore National Laboratory discovered that the liquid cooling system of their Cray-2 supercomputers decomposed during extended service, producing some highly toxic perfluoroisobutene.[5] Catalytic scrubbers were installed to remove this contaminant. With that much constant heat, what chemical might be best/most practical I wonder. https://en.m.wikipedia.org/wiki/Novec_649 https://en.m.wikipedia.org/wiki/Novec_649 https://en.m.wikipedia.org/wiki/Hydrofluoroether https://en.m.wikipedia.org/wiki/Hydrofluoroether

jdietrich 3y ago

15kW dissipated over that area isn't particularly challenging for an industrial water cooler - within reason, you can just keep cranking up the flow rate. What'd scare me is power delivery, because they've probably got >10,000 amps going to the die. https://www.eetimes.com/powering-and-cooling-a-wafer-scale-die/ https://www.eetimes.com/powering-and-cooling-a-wafer-scale-d...

buildbot 3y ago
20K amps (!!!): https://vimeo.com/853557623 https://vimeo.com/853557623 They use probably the fanciest piece of rubber (and metal) ever made to pass the power in frontside to the die.
- Dylan16807 3y ago
  Doing it with all that water needing to get everywhere is definitely a feat. But the power itself isn't too bad. A square millimeter of wire can comfortably carry 20 amps, and you can scale that up pretty straightforwardly. It looks like each of those 84 rectangles has to deal with 240 amps and has multiple square centimeters of contact with the voltage regulator card above it.

SAI_Peregrinus 3y ago

Direct-die vapor phase change cooler? That tends to be the fastest way to get heat out of a chip and to a big radiator. For industrial applications the need to run a big fan & a compressor are less problematic.

deleted 3y ago
[deleted]