Firefly and PC GAMESS-related discussion club

 
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Alex Granovsky
gran@classic.chem.msu.su

I have been routinely using clusters based on dual six-core Intel
Westmere processors for a couple of years (starting with early
engineering samples and now using production chips). Unfortunately,
I do not have access to Magny-Cour AMD processors so I have no
performance data for them. As far as I understand, they are not a true
12-core but rather are something in between two six core processors
on a single chip and true 12-core CPUs. I guess that depending on the
type of job you can find any of two configurations faster. Note,
24-core system is very fat node and this can be important for
applications limited by memory bandwidth. I'd suggest you to ask your
supplier to provide these two different systems for your tests so
you'll be able to put the workload of typical jobs you are running
most often on them and decide based on the results of tests.

I'll post more info to this thread when I have it.

All the best,
Alex

P.S. As to Windows vs. Linux, Firefly performs equally well under
both of them, so it is up to you to decide. I'd recommend Linux
because you'll be able to allocate more memory; however, this
is not related with specific Windows problems but rather with
limitations of Firefly which is still 32-bit.

On Wed Nov 2 '11 3:08pm, Thomas H. wrote
----------------------------------------
>Dear all,

>Which configuration should be better according to the computing time:
>a)     24 Core AMD Opteron (e. g. Dual-CPU AMD Opteron 6168 (12 core)) or
>b)     12 Core Intel Nehalem (e. g. Dual-CPU Intel Xeon L5640 (6 core))?

>If I take a look to the published Firefly performance tests I see only a significant computing time difference between Intel and AMD if a low number (one or two) cores are used. If more cores are used the computing time difference is quite small, so the number of cores are more important. So I would prefer the configuration with 24 cores AMD Opteron instead of only 12 cores Intel Nehalem. Am I right?

>I was wondering, weather this is right in case of Firefly, because in case of ADF/BAND I got the information of the supplier, that there is no significant difference in the computing time between 24 cores AMD Opteron and 12 cores Intel Nehalem, because of the multi-threading functionality of the Intel Nehalem cores. And because of the lower needed number of cores in case of Intel the memory size can be reduced in comparison to the AMD CPU. So finally the Intel version would be preferable in the case of ADF/BAND.

>And one more question: Is there a significant difference in the computing time between the Firefly Windows (Win 7, 64 bit) and Linux version (also 64 bit)?

>Thanks in advance,

>Thomas
>

[ This message was edited on Mon Nov 7 '11 at 11:18am by the author ]