eXtreme!
eXperimental!
eXplosions!
etc...
Take your pick. I created it to replace the useless SPSP mode to see if I
could relax precision further than SPFP does and still maintain NVE
stability. It was a work in progress until GM204 made it suddenly
relevant...
I hope to get to it during Christmas break...
On Sun, Nov 23, 2014 at 4:51 PM, Parker de Waal <Parker.deWaal.vai.org>
wrote:
> Thanks for the quick reply, these benches are much better!
>
> However that leads me to another question: I can't find any information on
> SPXP... is it `dangerous` to use SPXP results? Also what is SPXP? single
> precision eXtreme point?
>
> Parker
> ________________________________________
> From: Scott Le Grand [varelse2005.gmail.com]
> Sent: Sunday, November 23, 2014 7:32 PM
> To: AMBER Mailing List
> Subject: Re: [AMBER] 4x GTX 980
>
> Also you need to compile to SPXP (not the default SPFP)...
>
> We're working on this... This is a real curveball they threw us this
> round. The worst-case scenario is stabilizing SPXP and leaving SPFP as
> is...
>
>
> On Sun, Nov 23, 2014 at 4:31 PM, Scott Le Grand <varelse2005.gmail.com>
> wrote:
>
> > Turn off SLI...
> >
> >
> > On Sun, Nov 23, 2014 at 4:22 PM, Parker de Waal <Parker.deWaal.vai.org>
> > wrote:
> >
> >> Hi Scott,
> >>
> >> After putting together the machine and running the benchmark suite I've
> >> noticed that my performance is significantly worse than your numbers.
> >> Specifically, while running 2x cards in SLI mode the FactorIX-NVE I'm
> only
> >> getting:
> >>
> >> | Average timings for last 1000 steps:
> >> | Elapsed(s) = 5.19 Per Step(ms) = 5.19
> >> | ns/day = 33.28 seconds/ns = 2596.11
> >>
> >> Interestingly I get the almost the same number when running with a
> single
> >> gpu.
> >>
> >> I'm wondering if I set this up correctly as I've never built an SLI
> >> machine before. However, I have noticed that having SLI on ($
> >> nvidia-xconfig --sli=on) disables gpup2p (according the gpup2p checker).
> >>
> >> Are there settings you are supposed to specify to get that kind of
> >> performance?
> >>
> >> Best,
> >> Parker
> >> ________________________________________
> >> From: Scott Le Grand [varelse2005.gmail.com]
> >> Sent: Monday, November 17, 2014 5:42 PM
> >> To: AMBER Mailing List
> >> Subject: Re: [AMBER] 4x GTX 980
> >>
> >> 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://scanmail.trustwave.com/?c=129&d=wvzy1IeuIEIHX-mZ248yeHqXVVxmdEgC71HNbs9p4A&u=http%3a%2f%2fwww%2enewegg%2ecom%2fProduct%2fProduct%2easpx%3fItem%3dN82E16811133194
> >> > >
> >> > > 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://scanmail.trustwave.com/?c=129&d=wvzy1IeuIEIHX-mZ248yeHqXVVxmdEgC71XIas1l4A&u=http%3a%2f%2fwww%2enewegg%2ecom%2fProduct%2fProduct%2easpx%3fitem%3dN82E16835132022
> >> > >
> >> > > 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
> >>
> http://scanmail.trustwave.com/?c=129&d=wvzy1IeuIEIHX-mZ248yeHqXVVxmdEgC7wPBa500tw&u=http%3a%2f%2fambermd%2eorg%2fgpus
> >> 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://scanmail.trustwave.com/?c=129&d=wvzy1IeuIEIHX-mZ248yeHqXVVxmdEgC71LJbcA35w&u=http%3a%2f%2flists%2eambermd%2eorg%2fmailman%2flistinfo%2famber
> >> > >>
> >> > >
> >> > >
> >> > _______________________________________________
> >> > AMBER mailing list
> >> > AMBER.ambermd.org
> >> >
> >>
> http://scanmail.trustwave.com/?c=129&d=wvzy1IeuIEIHX-mZ248yeHqXVVxmdEgC71LJbcA35w&u=http%3a%2f%2flists%2eambermd%2eorg%2fmailman%2flistinfo%2famber
> >> >
> >> _______________________________________________
> >> AMBER mailing list
> >> AMBER.ambermd.org
> >>
> >>
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> >> _______________________________________________
> >> AMBER mailing list
> >> AMBER.ambermd.org
> >>
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> >>
> >
> >
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>
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Received on Sun Nov 23 2014 - 17:30:02 PST
