A few weeks ago I put this GPU, this RTX 3080 into a tank of dielectric coolant and experimented
with immersion cooling.
It worked awesome…
at first.
The temperatures were great, this little radiator had plenty heat rejection capacity for one
graphics card - the whole thing was really quiet and I liked looking at it when I would
come into the office, at first.
Well..
Engineered Fluids Electrocool dielectric coolant has a materials compatibility list.
A list that I sort of ignored when I initially set up this little system.
I didnt realize that the incompatible materials get destroyed by this stuff PRETTY quickly!
I had it all set up in this plastic fish tank - I dont know what type of plastic it was,
but it was the wrong stuff!
It got really brittle, and of course while I was on a trip to minnesota, Sarah called
me to let me know it blew a hole in the side of the tank and immersion cooled my whole
desk and a lot of the floor.
What a mess.
Anyway - NOW we all get to learn the steps to removing a GPU from an immersion cooling
setup and getting it back to work in the air, like NVIDIA intended.
First, EC110 is an oil based fluid.
So this card was never going to just, dry off.
You need to use some sort of solvent.
I had a can of DS-100 solvent from my ASIC Immersion setup Ive been experimenting with,
so thats what I used.
I just put the GPU in a bucket and dumped solvent over it and into the bucket - then
I took a second bucket, put the graphics card in there and dumped the solvent from the first
bucket into the second bucket and repeated that a few times until I was pretty sure that
where ever that stuff COULD go, it did do.
Im confident that if not the coolant, then surely the solvent would have ruined the thermal
paste and pads that help transfer heat off the card to the heat sinks, so the next step
was to get this thing apart and replace all of that, and clean off whatever else was still
oily inside.
These cards are pretty easy to take apart - just get a tiny screw driver set, this kit
is from iFixit, ill leave a link in the description, and start t taking screws off, wherever you
can find them!
Maybe take video or pictures as you get deeper into the card - these screws are not all the
same size and I ended up having a little trial and error when putting it back together.
Anyway, got the fan shroud off - these four screws on the back of the card are all that
holds on this heat sync - but people are finding out that to get memory temps down on air cooling,
it helps a lot to get some thermal pads on the BACK of the memory as well as on the front,
so I took the rest of these screws out to get the back plate off also.
Turns out there were already some pads back here, and a heat pipe!
Side note - im no expert computer builder or anything, if you want like perfect measurements
and really technical information, there are other guys making videos about that - I just
cut these things up and slapped them on where I feel like they should go!
But I know what memory chips look like, and thats primarily what were trying to cool down..
Anyway, first thing to do was to get all of the old paste and pads off of the card.
I used the little plastic wand thing from this ifixit kit, and some rubbing alcohal
to scrape off and clean up the surfaces pretty good.
Then got out some thermal pads and went to work!
These little chips on the side here had their own heat sink as part of the frame - so they
got some 2mm pads.
This stuff doesnt have to be continuous, you can cut it up into pieces and itll work fine.
I chopped up some more for the memory modules - this black plate makes contact with them,
and then the main heat sink sits on this plate, so there are actually pretty good indicators
on the plate of where to put thermal pads.
Before getting everything all sticky greasy with paste - I flipped it over and put some
real thick, 3mm pads on the back side of the memory modules.
I dont know what these other smaller chips are - but on the front they had pads, so I
went ahead and cut up some more to sandwich those fellas to arm them with as much heat
mitigation as I could fit in there.
On the front side - I put pads all over the place!
And if there are any experts among you, you may force what happens when I turned this
thing on..
Anyway, I smeared on a bunch of thermal paste (yeah - way too much thermal paste, what are
you going to do?)
And notice the swirl pattern of paste on the heat sink side - that plays a key role later
in this video.
I put the heat sink back on, put the back plate back on, took a quick video call from
Blake at Musk Miners (my trusted US based ASIC hardware supplier, he really did call
me during this, not a sponsored event) plugged in the fans, put the shroud back on, and quickly
threw together a motherboard to run this thing on.
Everything fired up as expected - the GPU fan started going suspiciously fast for a
bit but it cooled itself back down…
BUT, as soon as I started mining - memory junction temperature was fine, really good
actually but the hotspot temp shot up to 110 and the card just turned itself off..
Well that was unexpected..
But clearly I did something wrong..
SO I took the card back apart, evidently my camera had stopped but that swirl of thermal
paste was still on the heat sync where it was supposed to be pressed onto the main GPU!
Lesson learned, this area around the outside of the GPU does not get pads - they were stopping
the heat sink from making contact with the GPU.
took those pads off, Im not sure if its supposed to get anything, but I smeared a bunch of
thermal paste on it anyway, put the heat sink back on and fired it up - and this time it
was all golden!
In fact, by changing out the pads on the back - now while mining at 92MH, the memory junction
temps on this card, which normally hover around 100 degrees C - were just right at an icy
cool 90 degrees!
Long story short - if you try immersion and change your mind, or destroy the whole setup
by using the wrong tank AND pump AND lines - thats a triple double - before going back
to air cooling, take the card apart, scrape off the old thermal stuff and put in new thermal
stuff.
If you have THIS card and want THESE temperatures, look at this, you can just do what I did.
Unfortunately every manufacturer also makes their own heat sink and stuff will be in different
places.
My liquid cooled 3080’s have a completely different looking heat sink and no back plates
at all!