GTX 980 is well on its way to provide blowout AMBER numbers despite the
claims of its hopeful competitors (Really, will they ever learn? Nah...)...
It didn't do so out the door because the performance a of key HW
instruction was crippled relative to Kepler (llrintf).
In the near-term future, either NVIDIA will address the above or we will
adopt a workaround to stabilize SPXP and make it the preferred operational
mode for GTX9xx cards. In fact, if you're using a thermostat, I *think*
you can run JAC NVE in SPXP today at ~185 ns/day out of the box. This is
of course the *correct* mode for directly comparing performance of unstable
crappy MD code, but at least our crappy unstable mode is deterministic.
Scott
On Sun, Nov 16, 2014 at 8:16 PM, James Maier <jimbo.maier.gmail.com> wrote:
> **Please note that all experiences I've cited are for GTX 780s.
>
> On Sun, Nov 16, 2014 at 11:13 PM, James Maier <jimbo.maier.gmail.com>
> wrote:
>
> > 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
> > case.
> > Not that it matters, but the blue lights look exquisite against the green
> > GTX logo.
> >
> > http://www.newegg.com/Product/Product.aspx?Item=N82E16811133194
> >
> > 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:
> >
> > http://www.newegg.com/Product/Product.aspx?item=N82E16835132022
> >
> > 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
> > me.
> >
> > 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 ambermd.org/gpus 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.
> >
> > HTH,
> >
> > James
> >
> > On Sun, Nov 16, 2014 at 9:28 PM, Parker de Waal <Parker.deWaal.vai.org>
> > wrote:
> >
> >> 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
> >> _______________________________________________
> >> AMBER mailing list
> >> AMBER.ambermd.org
> >> http://lists.ambermd.org/mailman/listinfo/amber
> >>
> >
> >
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>
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Received on Mon Nov 17 2014 - 15:00:02 PST
