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Topic Title: AMD OPTERON 6282 SE
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Created On: 03/13/2012 05:16 AM
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 03/13/2012 05:16 AM
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SAREQ
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I buy 2 prosessor from two month and i want to know why WINDOWS 8 assigned thread to this prosessor 16 cor -16 threads

also i want to know if ECC DDRM3 1333 8 GB suitable for this prosessore or i should get 1600 or 1866

Edited: 03/13/2012 at 06:22 AM by SAREQ
 04/13/2012 02:52 PM
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Havaneiss Dei
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I may not be understanding your question. Doesn't the Opteron 6282SE present 16 Bulldozer cores (at 2.6-, 3.0-, and 3.3-GHz) in a 140W-TDP, 105W-ACP package? That sounds normal.

For RAM, you'll want to check the QVL for your specific motherboard. AFAIK, quad-channel DDR3-1333 ECC is acceptable with just about any Socket G34 board; some boards will support quad-channel DDR3-1600 ECC, and there may be a few out there that will support quad-channel DDR3-1866 ECC. Remember, though: not all quad-channel DDR3-1333 ECC is the same (as every other quad-channel DDR3-1333 ECC); not all quad-channel DDR3-1600 ECC is the same (as every other quad-channel DDR3-1600 ECC); not all quad-channel DDR3-1866 ECC is the same (as every other quad-channel DDR3-1866 ECC).

In other words, you can't just pick any (quad-channel) ECC DDR3 (in the speed rating you want) off the proverbial shelf and have it work properly.
 04/20/2012 08:26 PM
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MU_Engineer
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Originally posted by: SAREQ

I buy 2 prosessor from two month and i want to know why WINDOWS 8 assigned thread to this prosessor 16 cor -16 threads



also i want to know if ECC DDRM3 1333 8 GB suitable for this prosessore or i should get 1600 or 1866


I think I can help:

1. Each 6282SE has 8 CPU modules (two 4-module chips.) Each module has 2 threads. So, each chip has 8 modules with 16 threads. The Bulldozer microarchitecture used in the 6282SEs is unlike any previous AMD or Intel CPU and is based on modules that each handle two threads. The performance of a module is somewhere in between Intel's two-thread HyperThreading cores (which are about 10-15% faster on average than running only one thread on the core) and two cores on previous AMD chips (where two cores were right around twice as fast as one core.) Thus the "16-core" 6282 SE is not quite as fast as a 16-core chip made from previous Opteron cores clocked at the same clockspeeds the 6282SE is (AMD actually couldn't do that with the old cores, which is why they made these new ones), but it is much faster than a 16-thread (8-core) Intel HyperThreaded chip. The fact that running two threads on one module decreases performance slightly compared to running two threads on two different modules led AMD and MS to revise how the CPUs are represented to the OS. The "16-core" 6282 SE is thus seen as an "8-core, 16-thread" CPU in order to have each module load up with one thread before assigning more than one thread to any module. It's a hack that was put in place until Windows 8 properly addresses these considerably different CPUs.

2. From what I have heard, DDR3-1600 gives about a 5% performance boost over using DDR3-1333. DDR3-1866 is supposed to work with this CPU but with a bunch of restrictions. There is also no server-grade DDR3-1866 out there yet, so you're really looking at 1333 vs. 1600. If you have a bunch of 1333, use it. If you are buying all new RAM, go with the 1600 stuff as it is about the same price as 1333.

You probably also should get more than 8 GB if you are building a new system. You will want four memory modules per CPU, and 4 GB modules cost little more than 2 GB ones. You will thus want at least 16 GB (four 4 GB modules) per CPU.

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 06/19/2012 03:36 PM
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apahim
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Hello MU_Engineer,

Could you provide some AMD documentation about your information "Each module has 2 threads. So, each chip has 8 modules with 16 threads."?
All AMD docs are saying 6282SE has 16 cores [1], but linux servers are probing 8 cores + 8 threads, as you said.

Thanks in advance.

[1] - http://www.amd.com/us/products...ges/model-numbers.aspx
 06/19/2012 11:39 PM
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MU_Engineer
Dr. Mu

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I cannot find any AMD documentation but the CPUID() function in Linux reports that the CPU has one physical core and one logical core per module. The reason it does this is because the best performance is obtained from Bulldozer CPUs when you schedule only one thread per module until the number of threads > number of modules.

The whole "how many cores does a Bulldozer really have?" question is a huge controversy. Your Opteron has eight modules. Each module has one decoder frontend, one CPU, one L1 data cache, two integer pipelines each with their own scheduler and L1 instruction cache, and one L2 cache. AMD considers the integer pipelines to be the part that defines a CPU core, so there are two cores per module and 16 cores per 8 module CPU.

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