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.

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Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us