[Beowulf] Re: Opteron 275 performance

Robert G. Brown rgb at phy.duke.edu
Wed Jul 27 19:54:35 PDT 2005


Steve Cousins writes:

> 
> On Wed, 27 Jul 2005, Ben Mayer wrote:
> 
>> Correct me if I am wrong but I am under the impression that each CPU
>> has one memory controller, independent of the number of cores. So if
>> you go dual core those cores are sharing a memory controller. What you
>> have in the end if you go dual core with 2 CPUs is 4 cores with 2
>> memory controllers.
> 
> Yes.  This is the sort of thing I am worried about.  I remember running
> into problems with our Dual PIII cluster where there was a significant
> difference in performance when ran we our models using 8 nodes using both
> CPU's per node vs. 16 nodes using one CPU per node.  Something like 40%
> faster on the single CPU per node runs. I guess the only sure-fire way to
> know is to get our hands on a Dual Core system and see how our model
> performs.  Anyone got one available for testing... ;^)

Dead on the money on all accounts.

I'd be surprised if you don't get offers from several vendors.  Michael
Will of Penguin is on list, for example.  Most of the serious
linux/cluster vendors are happy enough to provide access to a system or
cluster for testing purposes, especially if they sense a sale at the end
of it.  Or even a possible sale;-).

    rgb

> 
> Steve
> ______________________________________________________________________
>  Steve Cousins, Ocean Modeling Group    Email: cousins at umit.maine.edu
>  Marine Sciences, 208 Libby Hall        http://rocky.umeoce.maine.edu
>  Univ. of Maine, Orono, ME 04469        Phone: (207) 581-4302
> 
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