[MITgcm-support] AMD quad core

[Gøran Brostrøm]

Dear Dierk

MITgcm is very craving on memory bandwidth. The memory bandwidth is 
often shared between dual processors and multiple cores. Therefore 
adding cores and processors on a chip may not improve the performance. I 
used to check 171.swim in spec2000 (http://www.spec.org/cpu2000) for 
performance on different processors (this test is somewhat more craving 
than MITgcm but it is nevertheless the one to look at). See if you can 
find a similar system on spec2000 for guidance. I do not know what is a 
good test in the new spec system.

Sincerely
Gøran


> Can someone please refresh me as to why "AMD Quad Cores are Terrible"
>
> We have a system that currently runs with two DUAL-CORES 2214 and we 
> are thinking of adding 4 more nodes with either two Dual or two Quad 
> Cores.. We use gigabit ethernet to connect our nodes and we take a 
> pretty good hit each time we have to communicate to another node.
>
> It would seem to me that the running with two 2xQUAD would be better 
> than running four 2xDUALS for the same 16 cpu'?
>
> I do see the L2 cache is smaller in the Quad cores.
>
> thanks in advance.
>
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
>    Dierk Polzin
>
>    mailto:dtpolzin at wisc.edu    608-334-3574 cell
>
>   Skype: saildirk
>
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