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+--- Thread: 8/10GPU 3080ti 2u/4u chassis? (/thread-10708.html)
8/10GPU 3080ti 2u/4u chassis? - cybhashcat - 04-03-2022
Hey friends.
The previous rig i purchased for my office was for 8 2080ti cards, on a Gigabyte 2u g29-281 chassis - and everything has been working fine for years.
My office wants to purchase a rig for cracking passwords and they want to go big, either 8 or 10 GPU's, all of them 3080TI's.
I just got off the phone with one of our provider and they claim you can no longer fit these consumer cards on 2U or 4U chassis, Is there any truth to that statement? i find it very odd but wanted to get your expert opinion first.
thank you!
RE: 8/10GPU 3080ti 2u/4u chassis? - lapwing - 04-27-2022
Hi Cybhashcat,
This is partly true and therefore your vendor has indeed some truth in their statement on the 2U 8GPU Gigabyte servers. First thing is you will have to fit blower design cards with power connectors on the rear of the card. Such as the Asus Turbo GeForce RTX 3080 Ti 12G or the Gigabyte GeForce RTX 3080 TURBO 10G (or utilize a soldering iron }> ). Secondly there is another important issue with this setup: the chassis has been designed with dual direction passively cooled GPUs in mind. The front GPU canisters of the chassis install the GPUs reversed(!) therefore the airflow of an actively cooled blower design card will be trying to push air against the air direction of the Chassis fans and therefore will have a terrible (short and hot) life as hot air is being recycled and the GPU fan will have to fight very hard against the more serious chassis fan. It is actually a wonder that it has been working for you! You can resolve this by removing the cap and the fan of the GPU making it a passive two way air card, but this will most certainly void your warranty. This method works fine for cards up to 250W but I'm unsure about these power hungry beasts. I have been unable to find the GPU-power specifications of these chassis anywhere but I do know that the cable dimensions of the 8 pin power connectors are quite undersized in my opinion therefore I'm not sure weather you can safely house cards above 300W. One more additional note: these chassis have an undocumented side air intake which provides the rear GPUs with "fresh" air rather than reuse warmer air from the front GPUs. This is a good approach as long as your rack is able to supply cold air on the sides of the chassis, if not you will be recycling (quite) hot exhaust air from the rear of your racks.
I hope this helps!
RE: 8/10GPU 3080ti 2u/4u chassis? - cybhashcat - 05-01-2022
Hey man!
So first of all, i really appreciate you talking the time to answer, i apologize it took me so long to see it.
Most of this makes sense to me, and yes, my 2U setup had the cards stripped of their heatsinks and fans - which aligns with what you said.
However, the only thing that confuses me is what you said about the blower fans:
(04-27-2022, 03:27 PM)lapwing Wrote: therefore the airflow of an actively cooled blower design card will be trying to push air against the air direction of the Chassis fans and therefore will have a terrible (short and hot) life as hot air is being recycled and the GPU fan will have to fight very hard against the more serious chassis fan.
So these GPUs that are listed as supported under 2U servers have no cooler? its all a heat sync that is supposed to be cooled by the chassis fans?
example: https://www.gigabyte.com/Enterprise/GPU-Server/G292-Z42-rev-A00
RE: 8/10GPU 3080ti 2u/4u chassis? - lapwing - 05-26-2022
(05-01-2022, 05:45 PM)cybhashcat Wrote: So these GPUs that are listed as supported under 2U servers have no cooler? its all a heat sync that is supposed to be cooled by the chassis fans?
example: https://www.gigabyte.com/Enterprise/GPU-Server/G292-Z42-rev-A00
Well I have no statement from Gigabyte about this but as far as my experiments go that is true. Actually in the supported hardware list the RTX6000 is listed explicitly with the term "passive" which agrees with my findings.
You should be able to use blower fan GPUs in the rear canister positions as the airflow is in the correct direction there.
But please keep in mind that using GPU fans may result in a situation that the Chassis fans could be "driving" the GPU fans. I don't know the design of the GPU fan PWM driver but it might become unhappy when the GPU fan starts to generate energy in stead of consuming energy.
In short: remove GPU fans and caps (but do keep the heatsinks ;-P ) or buy passive cards.
Cheers