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I am planning to deploy two Ethereum mining rig in my store room. Both rigs will have a total of 14 RX 570 GPU's and rest of usual suspects. The GPUs and PSU will be running at full usage while other items nearly at idle.

I don't have any ventilation in store at the moment so I will be installing a few 120mm fans (maybe 6 or 9) as intake on one side (in the wall) and exhaust on the other.

Can someone give me an estimate (very rough one) of how much CFM I should intake/exhause in order to sufficiently cool these 2 rig?

EDIT: Apologies for the delay but my query was to install fans in the walls on the store room and not on either side of case. The case will have its own fans but I wanted to know how much CFM air to bring in the store room from one wall to exhaust it at another.

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  • $\begingroup$ Logic would suggest 1 fan for each GPU as a minimum... So consider 14 on each side... $\endgroup$
    – Solar Mike
    Sep 13, 2017 at 9:05
  • $\begingroup$ Without a value of the heat output from each processor etc and any temperature maximum you want in the store room then design so that you can add further fans or larger fans at a later date if necessary. $\endgroup$
    – Solar Mike
    Sep 13, 2017 at 10:05
  • $\begingroup$ Apologies for the delay but my query was to install fans in the walls on the store room and not on either side of case. The case will have its own fans but I wanted to know how much CFM air to bring in the store room from one wall to exhaust it at another. $\endgroup$
    – Kim
    Sep 13, 2017 at 17:32
  • $\begingroup$ My points about heat output and max temperature still apply... $\endgroup$
    – Solar Mike
    Sep 13, 2017 at 17:42

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Instead of following Solar Mike's answer of simply adding one fan per side, I'd rather try to make it more compact by thinking about an intelligent layout, which incorporates directing the cooling flow to the GPU surface instead of just blowing parallely to its board. An example is shown in the attached image. This could reduce the needed amount of fans to $\left(n-1\right)/2$, with $n$ being the amount of GPUs. GPU rig with 3 GPUs and two different kinds of flow diverters

The flow diverters between the GPUs are of two different shapes. The left one, the bow shaped ones, are more optimized. The start at an angle parallel to the flow and then divert the flow to the GPU surface. This is good for having a low pressure loss and thus a high mass flow, but difficult to manufacture.
On the right side is a simple flow diverter. This could be just some metal sheets, which are connected by some simple metal bar at the top and bottem side (shown with dots) which also is with where they could be mounted to the case. Easy to manufacture and quite ok flow diverting.
Without any diverter you'll need an ALOT higher mass thoughput to get some turbulence with gets the air to the GPU surface.

edit:
If the GPUs already have their own fans, forget about the diverters and just make sure that fresh air is only coming from one side. That means to have the output side of the GPU fans facing away from the case fan. Perhaps even make some kind of a closed case at the backside, top and bottom of the GPUs to avoid pushing fresh air out at these sides!

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  • $\begingroup$ How are these fans in the wall for inlet and extraction as the OP asked in the question? $\endgroup$
    – Solar Mike
    Sep 13, 2017 at 10:00
  • $\begingroup$ Is the question as posed by the OP about moving the air into and out of his store room? $\endgroup$
    – Solar Mike
    Sep 13, 2017 at 10:03
  • $\begingroup$ @SolarMike I'm sorry, but I don't really get what you are asking? The fan in my image can be mounted in the inlet wall, if the inlet wall is the rig-casing. Which would be the best way to go. If the wall is farther away from the rig, he will just have a laminar and undirected flow to the GPUs, which doesn't really help with getting the warm air away. $\endgroup$
    – JE_Muc
    Sep 13, 2017 at 10:06
  • $\begingroup$ The inlet wall for the OP is his store room wall... not the casing $\endgroup$
    – Solar Mike
    Sep 13, 2017 at 10:08
  • $\begingroup$ Yeah, but why shouldn't it be possible to place the rig with the fans at the "inlet" wall where he wanted to mount the fans? So just make a hole in the wall at the place where the rig's fans will be. This will make a far better cooling flow inside the rig than placing the rig just somewhere in the room. Like this no exhaust-fans are needed on the exhaust wall, as long as the pressure loss is not too big. This means just having an exhaust hole in the exhaust wall of (at least) the same size as the inlet hole. $\endgroup$
    – JE_Muc
    Sep 13, 2017 at 10:17

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