[Beowulf] General thoughts on Xeon 56xx versus E5 series?

Vincent Diepeveen diep at xs4all.nl
Thu Sep 13 02:29:38 PDT 2012

On Sep 13, 2012, at 11:11 AM, Vincent Diepeveen wrote:
> e5 has 4 memory channels serving 8 cores. So that's 2 cores @ 4
> threads for each memory channel, just like 56xx.

I see on ark.intel the number of memory channels and number of cores  
of course
largely depend upon which type of e5 you buy, they really released a  
lot of them.

Not surprisingly they have a lot with 6 cores released as well, yet  
to my surprise
i also see they have 8 core cpu's with 3 memory channels.

Using 3 memory channels to serve 8 cores @ 16 threads under full load,
it's not very optimal let me tell you that.

Even a chessprogram already feels that difference.

Yet the reason is pretty obvious, some of the E5's use the older  
socket 1356 versus 2011 for the higher numbered E5's.
The new 2011 socket requires for 4 channels and multiples of 4 dimms.

Lately Intel has both in consumer market as well as in server/HPC  
market a LOT of different types of cpu's.

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