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

Orion Poplawski orion at cora.nwra.com
Fri Sep 14 08:04:47 PDT 2012


On 09/14/2012 08:54 AM, Vincent Diepeveen wrote:
> The memory controller is on die, so the bandwidth that the CPU itself delivers,
> independant from the number of channels, is dependant upon the CPU frequency.
>
> Higher frequency means more bandwidth simply with the given memory channels
> available.
>

Really?

http://ark.intel.com/compare/64590,64591,64587

Clock Speed		2 GHz		2.5 GHz		3.3 GHz
Max Turbo Frequency	2.8 GHz		3 GHz		3.5 GHz
# of Memory Channels	4		4		4
Max Memory Bandwidth	51.2 GB/s	42.6 GB/s	51.2 GB/s

>
> On Sep 14, 2012, at 4:41 PM, Orion Poplawski wrote:
>
>> On 09/14/2012 05:00 AM, Igor Kozin wrote:
>>> if memory bandwidth is your concern then there are models which boost
>>> it quite significantly. e.g.
>>> http://ark.intel.com/products/64584/Intel-Xeon-Processor-E5-2660-20M-Cache-2_20-GHz-8_00-GTs-Intel-QPI
>>>
>>> probably very few codes are going to benefit from AVX without extra
>>> efforts but BW is a clear win.
>>> i'm seeing a good speed up on some applications which can be
>>> attributed to higher BW.
>>
>> There are 6.4, 7.2, and 8 GT/s chips
>>
>> This is an interesting puzzle and the mid tier price point:
>>
>> DUAL INTEL XEON 6C E5-2640 (2.5GHz/7.2GT/s/15MB) CPU  [+ $1,810.00]
>> DUAL INTEL XEON 4C E5-2643 (3.3GHz/8GT/s/10MB) CPU  [+ $1,798.00]
>> DUAL INTEL XEON 8C E5-2650 (2GHz/8GT/s/20MB) CPU  [+ $2,270.00]
>>
>> So for BW limited one would go with the second two, but you have a big choice
>> between low cores/cache high MHz and high cores/cache low MHz.
>>
>> --
>> Orion Poplawski
>> Technical Manager                     303-415-9701 x222
>> NWRA, Boulder Office                  FAX: 303-415-9702
>> 3380 Mitchell Lane                       orion at nwra.com
>> Boulder, CO 80301                   http://www.nwra.com
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-- 
Orion Poplawski
Technical Manager                     303-415-9701 x222
NWRA, Boulder Office                  FAX: 303-415-9702
3380 Mitchell Lane                       orion at nwra.com
Boulder, CO 80301                   http://www.nwra.com


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