-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi folks,
We've got a group who bought themselves a 16 core 1.5TB Westmere-EX system and are getting what they consider to be poor memory bandwidth compared to an older 8 core Nehalem-EP system. Same CPU clock speed (2.6GHz), same memory speed (1067MHz), but about half the memory bandwidth (single threaded). I've run my own tests with the Stream benchmark and can confirm the same. For instance, the Nehalem-EP system typically gets around 12GB/s for triad and the Westmere-EX system gets around 4.5 GB/s. Now I know that I can use 16 threads (one per core) on Westmere-EX and get far better performance, but that doesn't interest them. I realise that the memory controller architecture is very different between EP and EX models, but is there any inherent reason why that should result in such poorer single threaded performance? All the best, Chris - -- Christopher Samuel Senior Systems Administrator VLSCI - Victorian Life Sciences Computation Initiative Email: sam...@unimelb.edu.au Phone: +61 (0)3 903 55545 http://www.vlsci.org.au/ http://twitter.com/vlsci -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlJgrGMACgkQO2KABBYQAh+MUQCfX+dy3hCoteYfMy+hQ28jtAmd 8sUAn0+CFYHZ0hXGiQW5g8pXxFATuKU9 =7m5B -----END PGP SIGNATURE----- _______________________________________________ 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
