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Question Dual 3080 cooling question

Psynapsx

Junior Member
Feb 3, 2021
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hello,

I built a server with two 3080s and they are kinda close to each other. Do you think this will be an issue? (heat).
Gigabyte Eagle OC and Gainward Phantom GS. There is a 300w power limit on each.
Since this is a server and will go into a rack, noise is not a big issue and I can run the fans in the case at higher RPM
I also I swapped the middle fan wall to 3x Noctua NF-P12 redux-1700 PWM since then. Exhaust fans are 2x Noctua NF-R8 redux-1800. CPU is AMD Epyc 32 core with Noctua NH-U9-TR4 SP3.

thank you
 

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Fallen Kell

Diamond Member
Oct 9, 1999
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Well it depends on the rest of the case. Does the case have a good amount of fans at the front that blow air from front to back?

If the case does, I would say there shouldn't be an issue (other than you having the heatsink/fans on your CPU oriented wrong for front to rear cooling, not sure if that can be fixed though).
 
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Psynapsx

Junior Member
Feb 3, 2021
4
0
6
Well it depends on the rest of the case. Does the case have a good amount of fans at the front that blow air from front to back?

If the case does, I would say there shouldn't be an issue (other than you having the heatsink/fans on your CPU oriented wrong for front to rear cooling). I don't know the exact socket that is or the exact heatsink, but I know noctua makes ones that can be oriented either way by just swapping out the screw on attachment at the bottom for most sockets.
thank you for the response.
The case has two Noctua NF-P12 redux-1700 PWM at the front, I just installed them today. It's the same fan I have in the middle fan wall
It's a Asrock Rack romed8-2t motherboard, SP3 socket.
This is the heatsink

I do not see any way to orient it differently
 

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Ajay

Diamond Member
Jan 8, 2001
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Looks from your photo that you only have 2x (80-92mm) fans for exhaust. Unless they are screaming high rpm deltas or something like that, you won't be pushing enough CFM through the chassis. Assuming, you are going to run high sustained loads on the GPUs. IMO.
 

Fallen Kell

Diamond Member
Oct 9, 1999
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Going by the rear exhaust fans really doesn't tell you the information on a server Ajay. In my server (a lightly modded Supermicro SC846), I don't even have rear exhaust fans installed because the mid located fanwall is more than powerful enough to pull air in from the front and push it out through the rear of the case. Now like I said, it is slightly modded, as in I removed the original fanwall (which used 3x92mm fans) and replaced it with 3x120mm fans, and I sealed any gaps or holes in the chassis behind the fanwall to the rear of the server (thus forcing the air to travel out the rear exhaust holes where additional fans could be mounted).

The fans I used were from the Noctua Industrial line. I can't remember if I went with the NF-F12 iPPC-2000 or iPPC-3000, but it was one of those two and they have more than enough power to handle my system (that said I do not have GPUs in there, but I do have 12 hard drives in front of them and 2 behind them as it is a storage server, plus the 2xXeon 6c/12t CPUs and 192GB RAM).

The reason for the modifications was to replace the 92mm Delta fans that ran at 7000+ RPM and were LOUD, with bigger fans that could move just as much air but it quietly. My network switch is louder than my storage server.

Psynapsx, yeah, I looked up that particular Noctua heatsink, and you are right, it doesn't look like it can be mounted the other way, which really kind of sucks a bit in your case. It is not bad, just not optimal.
 
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Ajay

Diamond Member
Jan 8, 2001
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Good point. I have worked on servers that had no back fans, just a large grill area. There were 4 or 5 ear splitting 80cm fans along the mid fan section (and two deep as well). One, older, storage server I worked with only had 40mm fans on each drive bay. The fans would routinely fail and we often would get temperature warnings on the raid arrays in the summer (underspecced AC in the server room). I was replaced the 3 92mm, 1200 rpm fans in the back with some 3000 rpm fans and the temp problems went away.

Anyway - I guess the only way to know for sure is to try it out and monitor GPU temps before you rack mount it.
 

Psynapsx

Junior Member
Feb 3, 2021
4
0
6
total it has:
front: 2x Noctua NF-P12 redux-1700 PWM
middle fan wall: 3x Noctua NF-P12 redux-1700 PWM
exhaust: 2x Noctua NF-R8 redux-1800 PWM
cpu: 2x NF-A9 PWM

It still has the stock middle fans on the pic. Those are louder and move significantly less air than the Noctuas I replaced them with

it does not have any HDDs as this is part of a larger cluster and there is a Supermicro storage server there.
It has 5x nvme SSDs in the front but those mounted near the top do not really block any airflow.
Cable management is bad with this one as the stock power cables are too rigid.

I will try to find something to stress test this on Ubuntu before moving to its final place.
Stress testing two 3080 at the same time on Ubuntu without a display turned out to be a challenge so far, kinda.
 
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Fallen Kell

Diamond Member
Oct 9, 1999
5,659
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I will try to find something to stress test this on Ubuntu before moving to its final place.
Stress testing two 3080 at the same time on Ubuntu without a display turned out to be a challenge so far, kinda.
Look up "GPU Burn" on google for a good stress test. You will need to compile it yourself, so you will need to read some directions and get the appropriate CUDA Toolkit versions and GCC compiler, but it is by far the best stress test I have ever found.
 

Psynapsx

Junior Member
Feb 3, 2021
4
0
6
Look up "GPU Burn" on google for a good stress test. You will need to compile it yourself, so you will need to read some directions and get the appropriate CUDA Toolkit versions and GCC compiler, but it is by far the best stress test I have ever found.
thank you I will give it a try
 

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