Being able to get an appreciable hashrate at 0.06 and not catch on fire at 0.15 will be difficult. I mean that's going to be drawing a lot of current, and making a lot of heat, per chip. The range I'm building for is about 0.07-0.12 like Phil said. Also hey, PlanetCrypto. Long time no see.
I missed ya'll. Good to communicate, again, with individuals with more than 4 active neurons.
That came out all wrong, but I think you get my meaning.
"Opinions are like butts, everybody's got one and they all stink."So here's the logic behind my stench:
It's obvious, any implementation is going to require logic level shifting. Cuz' comms to/from the chip are likely to be at 1.8V (or higher 2.5V, 3.3V, or dare I put forth 5V). So that complexity needs to be included in any design.
In vid part 1 (
https://www.youtube.com/watch?v=3zPpj1JYw38) he's demo'ing @ Vcore of .378V pulling ~6.0A which equals ~38GH/s per chip with efficiency @ .062W/GH/s.
COLD. A reasonable expectation is current draw will increase as the chip heats up, How much, no clue.
While not an easy 10A single phase buck design, it's doable and been done before. Heatsink optional.
My .06 thought was mirroring his demo. For an exclusively air cooled design I'd consider dropping that to .045 - .050. (buck efficiencies may drop horribly??).
That'd put it back to compac hash rates but with significantly better overall efficiencies.
vid 2, heatsink required.
Vid 3 where he "cranks it up" the heatsink is replaced with immersion cooling. Although the chip, conspicuously, is
NOT boiling the Novec fluid. So it ain't getting
THAT hot. And is probably still heatsink'able. For comparison Intel CPU's surface temperature in Novec run ~160F in 7100. And they boil like water on the stove. 3M (Phil Tuma) has vids on youtube showing this.
Novec 7000 boils @ 34C (93.2F), Novec 7100 boils @ 61C (141.8F), Novec 7200 boils @ 76C (168.8F), Novec 7300 boils @ 98C (208.4F)
The fact that the fluid is not boiling probably indicates poor heat transfer into the fluid (cuz' it's not hot enough to cause the fluid to change state) i.e. it can't contribute enough energy to rise above the latent heat of vaporization curve. Contributing to my belief that even at that Vcore/clock rate/current draw it's still heatsink'able and doesn't require immersion cooling to survive. Is it gonna' get hot, HELL YES. Does it require esoteric cooling, don't think so. Non boiling fluid provides little convection fluid flow, thereby leaving hot fluid on/near the surface of the chip. And even then, the fluid didn't boil.
The buck to drive it is another potential bone of contention. Cuz' it's drawing just under 40A (38.8A) @ a Vcore of ~.580V
PER CHIP. Imagine the current draw of a string of 3 or 4 chips. Similar to the current draw that'll start a car (albeit at a higher V). Unless somebody knows of some magic I'm not aware of, that's probably a multiphase buck. Probably 4, 5, or 6 phases at least for dependability and longevity. Each supplying 10A+. These are a bitch to design, increase component cost, and copper trace content/width/cost/board real estate. All in all, would us immersion cooling guys like to see it, YUP. Matter of fact why not drive it to 60A
. Is it the market segment GS is trying to service, HELL NO
Hence my upper limit cap of .15W/GH/s for
this project.
Nuff said, time to lurk.