Dynamic Power Management: A Quantitative Approach
by Johan De Gelas on January 18, 2010 2:00 AM EST- Posted in
- IT Computing
More Performance Please!
Now let's push the processor cores to their best performance.
When the going gets tough, the tough get going. The L3426 has a very tight TDP limit with no headroom for any extra Turbo Boost action. The X3470 has a TDP limit with a large margin, and as a result it's still capable of boosting the clock speed a bit higher (3.066GHz) when running eight threads.
At the same time, this graph shows how superior the integer engine of the "Nehalem" based cores is over AMD. A 1.9GHz quad-core offers about the same performance as a 2.9GHz quad-core. It also shows that for - well multi-threaded - integer applications, AMD's six-core was a decent countermeasure.
Turbo Boost delivers better performance, but comes with a power price. The influence is not really shocking at the system level - 9% higher power - but it is significant if you only look at the processor power level. We are still working on our methodology to measure power at the component level, but looking at the idle power and the spec sheets we can estimate CPU power rather well. Looking at the CPU level, Turbo Boost probably needs from 15% to 17% more power to the CPU VRMs.
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UrQuan3 - Thursday, January 21, 2010 - link
I'm trying to remember for 2008, but wasn't there a way to either force or suggest thread/core affinity? It looks like the scheduler was hopping all over the place on the Opterons.JarredWalton - Thursday, January 21, 2010 - link
You guys better pay attention and answer this post, or his species will try to enslave and/or wipe out the entire galaxy! ;-)mino - Wednesday, January 20, 2010 - link
I mean, not, why do you use them for this article.They are fine examples of low-power platforms, even if from vastly different markets.
But,
WHY ON EARTH DO YOU KEEP TALKING LIKE THEY WERE COMPARABLE THROUGHOUT THE ARTICLE ???
IntelUser2000 - Wednesday, January 20, 2010 - link
By the way, I don't know if you have the settings wrong or that's how it works, the Turbo Boost mode is not affected on the Home PC versions of Windows. Balanced uses Turbo Boost just as well on my Windows 7 Home Premium with Core i5 661.JarredWalton - Wednesday, January 20, 2010 - link
I was wondering this as well, but I'm not familiar with Windows Server... what I do know is that Power Saver on consumer Windows OSes really limits the CPU frequency scaling features, and it sort of looks like Balanced on the Server OS has aspects of consumer "Power Saver" as well as some elements of "Balanced". Odd to see only two power settings available, where Win7 now has at least 3 and often 5.mino - Wednesday, January 20, 2010 - link
It seems a classic example of KISS strategy of choosing the most-sensible options and so reducing decision complexity for IT people.Modes like "Max battery" have anyway no reason for existence on a server box.
RobinBee - Tuesday, January 19, 2010 - link
If you use your pc as a music server:Power saving methods ruin sound quality even if using a good sound card. The problem is »electronic« sound distortion. I do not know why this happens.
Also: The chosen number of IRQ pr. second in a net card can ruin sound quality too. Why, I do not know.
Anato - Tuesday, January 19, 2010 - link
I'm interested to see results from different operating systems which may be better at controlling processes in different CPU's. Namely no CPU hopping and is their power management as efficient as Windows is.Most interested at:
Linux and Solaris
JohanAnandtech - Tuesday, January 19, 2010 - link
Excellent suggestion :-). Problem is to keep the application the same. We currently tested SQL Server 2008 on Windows 2008 and of course this can not be done on Linux. However, I am not stranger to linux as a server.I am no fan of MySQL on Windows, but maybe this has improved. Would MySQL on Windows and Linux makes sense as a comparison?
maveric7911 - Tuesday, January 19, 2010 - link
Why not use oracle ;)