If it is memory bandwidth limited, you may want to consider AMD's EPYC which has 33% more bandwidth.
On Fri, Feb 16, 2018 at 3:41 AM, John Hearns via Beowulf < beowulf@beowulf.org> wrote: > Oh, and while you are at it. > DO a bit of investigation on how the FVCOM model is optimised for use with > AVX vectorisation. > Hardware and clock speeds alone don't cut it. > > > On 16 February 2018 at 09:39, John Hearns <hear...@googlemail.com> wrote: > >> Ted, >> I would go for the more modern system. you say yourself the first system >> is two years old. In one or two years it will be out of warranty, and if a >> component breaks you will have to decide to buy that component or just junk >> they system. >> >> >> Actually, having said that you should look at the FVCOM model and see how >> well it scales on a multi-core system. >> Intel are increasign core counts, but not clock speeds. PAradoxically in >> the past you used to be able to get dual-core parts at over 3Ghz, which >> don;t have many cores competing for bandwith to RAM. >> The counter example to this is Skylake which has more channels to RAM, >> makign for a more balannced system. >> >> I would go for a Skylake system, populate all the DIMM channels, and >> quite honestly forget about runnign between two systems unless the size of >> your models needs this. >> Our latest Skylakes have 192Gbuytes of RAM for that reason. Int he last >> generation this would sound like an unusual amount of RAM, but it makes >> sense in the Skylake generation. >> >> >> >> >> >> >> >> >> >> On 15 February 2018 at 14:20, Tad Slawecki <tslawe...@limno.com> wrote: >> >>> >>> Hello, list - >>> >>> We are at a point where we'd like to explore a tiny cluster of two >>> systems to speed up execution of the FVCOM circulation model. We already >>> have a two-year-old system with two 14-core CPUs (Xeon E-2680), and I have >>> budget to purchase another system at this point, which we plan to directly >>> connect via Infiniband. Should I buy an exact match, or go with the most my >>> budget can handle (for example 2xXeon Gold 1630, 16-cores) under the >>> assumption that the two-system cluster will operate at about the same speed >>> *and* I can reap the benefits of the added performance when running smaller >>> simulations independently? >>> >>> Our list owner already provided some thoughts: >>> >>> > I've always preferred homgenous clusters, but what you say is, >>> > I think, quite plausible. The issue you will have though is >>> > ensuring that the application is built for the earliest of the >>> > architectures so you don't end up using instructions for a newer >>> > CPU on the older one (which would result in illegal instruction >>> > crashes). >>> > >>> > But there may be other gotchas that others think of! >>> >>> Thank you ... >>> >>> Tad >>> _______________________________________________ >>> Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing >>> To change your subscription (digest mode or unsubscribe) visit >>> http://www.beowulf.org/mailman/listinfo/beowulf >>> >> >> > > _______________________________________________ > Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing > To change your subscription (digest mode or unsubscribe) visit > http://www.beowulf.org/mailman/listinfo/beowulf > >
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