When you mean a fan, you mean a "real fan" outside the chassis ? Or some fan in front of them on the chassis ?

Because, the Corsair Carbide 540 has two large fans in front of them, that's why I chose this one (and thought clever about it .. clearly I was wrong )

But funny thing, in your case... GPU0 being your MSI right ? It's the coldest one
You're running on open-air or chassis ?

Thanks !

Yes ! Got your point !

But when I look at things like this on Google :
http://2.bp.blogspot.com/-IEWl9KCMnQ0/TgJTJVdstRI/AAAAAAAAAXc/cGOR1nTYegs/s1600/bitcoin-mining-rig1.jpg
http://2.bp.blogspot.com/-80dE3jpLim8/TgJUUh9HCqI/AAAAAAAAAXg/j6kBoeHKOQs/s1600/bitcoin-rig-234x300.jpg

There's basically no air or spacing. How come ? They run at 100C+ ?

In my case, right now, there's about 4 slots left between the 2 cards. It's not crazy space, but it's more space than what I see on most pictures.

That's why I'm asking myself if that's the right card for a chassis, and/or if I should use horizontal/turbine fans like on the "reference" cards who will rear-extract the heat.

Thanks !

Thanks !

You got me ! I'm a SLI virgin
As a matter of fact, I haven't had this chance so far... because I'm a Mac user (where there was no SLI support so far)
But I already had up to 2 GPU inside my Mac Pro to run on multiple screens, and never had since so intense issue/difference.

Yes, I have seen those awesome rigs people are mounting on open air, but I thought it was because they were putting 5, 6, 8 cards on such a small place.
Plus I thought that with a 3 huge fan chassis that wouldn't be a problem to host only 3.

80C is not that bad, I agree, but it's because it has been underclocked a lot (850Mhz instead of 1050Mhz), but at normal speed I'm around 100C (after 10/20 minutes) and I feel like the card is about to die with that horrible noise.

Question : Is MSI a good brand ? Should I go any other one ? Is it the way the fans are made maybe, should I go instead with those "reference cards" (you know the ones with the turbine and rear extraction of the heat) ?

Hello,

I've bought 6x of this MSI r9 280X card on Amazon.
http://www.amazon.fr/MSI-GAMING-Graphique-Radeon-PCI-Express/dp/B00GSIFMB0/

I can't manage an incredible noise like a few mining rigs I have seen in here with 20/30+ cards on a plastic crates or ingenious systems like those, but my idea was to create a lot of "strong computers" that I could put at many places I have access to to manage and mitigate heat, noise, and power hazard.

So my first idea was too put 3 GPU (of those) per "computer".

I bought a Corsair Carbine 540 with a Corsair RM1000 1000W PSU
This one : http://www.amazon.fr/Corsair-Boitier-Carbide-Series-CC-9011030-WW/dp/B00D6GINF4 which has a nice airflow system.

And as for the MB I bought this one Gigabyte 990FXA-UD3 :
http://www.amazon.fr/gp/product/B00545BZOG/ref=oh_details_o02_s01_i03?ie=UTF8&psc=1

Now my issue.
I tried with only two cards for a start instead of 3, I installed BAMT 1.3 on a USB stick, everything went fine.

But soon, I realized my GPU#0 was starting to have a higher temp than GPU#1.
At first it was 1 celsius degrees, after a couple of minutes...
GPU#0 was ranging between 93/95+C (fan at 100%) and an awful noise !!!
GPU#1 was ranging at 70/75C (fan at 70/85%)

I immediately thought that it was because the cards were too close from each other, so I put GPU#1 at the bottom of the motherboard, leaving a good space between those.
It helped, but the difference is still the same... GPU#0 is now 85/90C, and GPU#1 is 65/70C.

I've tried to tweak the settings with cgminer, to lower the core, etc..etc.. it helped a bit... but GPU#0 is still at over 80C (with a slower hash rate).

I'm really worried having a card that could boil water while mining, especially when the other seems fine.

Since I have bought 6 of them, I thought it might be a wrong/defective card... so I removed it... and placed a new one instead.... exactly the same behavior (minus 1 degree better).

That's where I'm stuck now.

What could explain such a large difference ? Is it because the GPU is close to the chipset at this spot ? If I underclocked would it really help the matter (at same clock it should roughly act the same) ?

What should I do for you ?
Besides mining, those 2 cards could be inside a gamer chassis, and why would they act like this ? If I put 3 of those, the chassis would be on fire.
Is the 280X a bad choice ? Is this MSI a bad choice and other brands are fine ?

I'm totally in time to return everything to Amazon, so I'm open to everything... my only constraint is to keep them inside a chassis (and ideally 3 of them to maximize the capacity), so your feedback is welcomed

Thanks a lot guys !