Re: Performance on new 64bit server compared to my 32bit desktop

Clemens Eisserer wrote:
> Hi,
>
>
>>> This isn't an older Opteron, its 6 core, 6MB L3 cache "Istanbul". Its not
>>> the newer stuff either.
>>>
>> Everything before Magny Cours is now an older Opteron from my perspective.
>>
>
> The 6-cores are identical to Magny Cours (except that Magny Cours has
> two of those beast in one package).
>

In some ways, but not in regards to memory issues.
http://www.anandtech.com/show/2978/amd-s-12-core-magny-cours-opteron-6174-vs-intel-s-6-core-xeon/2
has a good intro. While the inside is like two 6-core models stuck
together, the external memory interface was completely reworked.

Original report here involved Opteron 2427, correctly idenitified as
being from the 6-core "Istanbul" architecture. All Istanbul processors
use DDR2 and are quite slow at memory access compared to similar Intel
Nehalem systems. The "Magny-Cours" architecture is available in 8 and
12 core variants, and the memory controller has been completely
redesigned to take advantage of many banks of DDR3 at the same time; it
is far faster than two of the older 6 cores working together.

http://en.wikipedia.org/wiki/List_of_AMD_Opteron_microprocessors has a
good summary of the models; it's confusing. Quick chart showing the
three generations compared demonstrates what I just said above using the
same STREAM benchmarking that a few results have popped out here using
already:

http://www.anandtech.com/show/2978/amd-s-12-core-magny-cours-opteron-6174-vs-intel-s-6-core-xeon/5

Istanbul Opteron 2435 in this case, 21GB/s. The two Nehelam Intel
Xeons, >31GB/s. New Magny, 49MB/s.

--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg(at)2ndQuadrant(dot)com www.2ndQuadrant.us