Re: [AMBER] 4x GTX 980

From: James Maier <>
Date: Sun, 16 Nov 2014 23:13:24 -0500

Hi Parker,

For the case, you can't go wrong with a HAF or almost anything with a fan
on the side. We went with the "Thermaltake Overseer" for our cluster; it's
a bit cheaper than the HAF and has a built-in SATA dock. It's a pretty neat
Not that it matters, but the blue lights look exquisite against the green
GTX logo.

We actually moved the fan that's pre-installed on the front to the side,
and put this "bgears b-Blaster" fan in the front instead:

120 mm, 103 CFM, not too expensive. We've not had any problems with them so
far after about 9 months.

As for the GPU, we've found the reference blower design to be more
effective when trying to squeeze four GPUs right next to each other. I
believe the blower style can generate higher (negative) pressure or
something, because the ACX, while great on its own, seems to do a terrible
job when something's directly occluding it. Our ACX GPUs were also higher
clocked though, so that's an important caveat to anything I wish I could
tell you more definitively.

But don't take my word for it; consult some BitCoin mining forums---they
seem to know all about this stuff. I believe a forum like that is where I
first read something about the reference style being better for >2 GPUs,
which seems to match our experience.

As Scott has cautioned, "superclocked is a 'super' way to get inaccurate
results." Sticking with a normal clockspeed will likely save headaches,
esp. as the 980s are a new design.

The other concern is power; you need a power supply with a rail with enough
wattage for all cards or with separate rails that all can drive a card. I'm
not sure if there is a single PSU that can "technically" (on paper,
following all stats to the letter) drive four GTX780s (require 42 Amps
each, I've only been able to find +12v with 133.3 Amps, plus about 5 V
through each PCI slot). If someone knows of an adequate PSU, please correct

In that regard, the GTX 980s look promising due to their lower power draw.
There are only 2 issues I can think of atm:

(1) 980s are "provisionally" supported by AMBER. This may not be an issue,
and according to there's an optimization coming.
(2) 980s are immature and thus the silicon is not likely as stable as, say,
a 780 or a Titan.

I'm guessing Ross, Scott, or anyone who has gotten their hands on some 980s
can chime in more about the above points.



On Sun, Nov 16, 2014 at 9:28 PM, Parker de Waal <>

> Hi Everyone,
> I apologize for the off topic post, however I'm currently building a 4x
> GTX 980 machine and was wondering if anyone had experience or insight on
> picking a proper case/fans. I'm worried that 4 cards will lead to
> overheating in most traditional cases.
> Additionally I'm wondering about the different fans on the GTX 980 cards,
> specifically the reference fan blower vs. the ACX 2.0 fans on the EVGA
> cards.
> Any insight would be extremely valuable.
> Best,
> Parker
> _______________________________________________
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Received on Sun Nov 16 2014 - 20:30:02 PST
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