if memory bandwidth is your concern then there are models which boost it quite significantly. e.g. http://ark.intel.com/products/64584/Intel-Xeon-Processor-E5-2660-20M-Cache-2_20-GHz-8_00-GTs-Intel-QPI probably very few codes are going to benefit from AVX without extra efforts but BW is a clear win. i'm seeing a good speed up on some applications which can be attributed to higher BW.
On 13 September 2012 15:48, Orion Poplawski <or...@cora.nwra.com> wrote: > On 09/13/2012 08:09 AM, hol...@th.physik.uni-frankfurt.de wrote: >>> Any general thought out there on Xeon 56xx versus E5 performance wise? >> >> We were comparing the performance of an older AMD with a newer AMD a while >> ago and found that the newer AMDs floating point performance was >> significantly reduced. >> >> It turned out that the kernel did not yet support AVX or FMA4 or some >> other new fancy bit of register blah blah so it reverted to some >> compatibility support for floating point operations. (I am not a kernel >> dev :) >> >> If your going to play with newer processors you have to make sure your >> kernel supports all the functions of that CPU. Kernel development can be a >> little way behind on mainstream releases. >> >> Ta, >> >> Andrew > > Thanks for the reminder of kernel support. RedHat states that RHEL5.7 should > support the E5 processors, so hopefully that means supporting the new > instructions. > > It seems the question before us is core scaling versus raw MHz. I've seen > many codes saturate the memory bandwidth before filling all of the cores and > it seems you have a trade off between MHz and cores these days at a given > price point. But perhaps that doesn't even matter if you're memory bandwidth > limited anyways. > > > -- > Orion Poplawski > Technical Manager 303-415-9701 x222 > NWRA, Boulder Office FAX: 303-415-9702 > 3380 Mitchell Lane or...@nwra.com > Boulder, CO 80301 http://www.nwra.com > _______________________________________________ > 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
