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Intel Turbo Boost vs. AMD Turbo Core Explained 198

Posted by kdawson
from the highly-pressurized-gas dept.
An anonymous reader recommends a PC Authority article explaining the whys and wherefores of Intel Turbo Boost and AMD Turbo Core approaches to wringing more apparent performance out of multi-core CPUs. "Gordon Moore has a lot to answer for. His prediction in the now seminal 'Cramming more components onto integrated circuits' article from 1965 evolved into Intel's corporate philosophy and have driven the semiconductor industry forward for 45 years. This prediction was that the number of transistors on a CPU would double every 18 months and has driven CPU design into the realm of multicore. But the thing is, even now there are few applications that take full advantage of multicore processers. What this has led to is the rise of CPU technology designed to speed up single core performance when an application doesn't use the other cores. Intel's version of the technology is called Turbo Boost, while AMD's is called Turbo Core. This article neatly explains how these speed up your PC, and the difference between the two approaches. Interesting reading if you're choosing between Intel and AMD for your next build."
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Intel Turbo Boost vs. AMD Turbo Core Explained

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  • Re:Huh? (Score:5, Informative)

    by Darkness404 (1287218) on Tuesday May 04, 2010 @07:51PM (#32092518)
    Essentially they both just detect if other cores can be powered down, power them down and then crank up the clock speed on the single cores because heat/power doesn't matter if the other cores are turned off or in the low megahertz. AMD's solution is like an afterthought because their architecture is older than Intel's while Intel's was built in to the architecture.
  • Re:PS. (Score:5, Informative)

    by icebraining (1313345) on Tuesday May 04, 2010 @08:06PM (#32092626) Homepage

    aptitude install cpulimit

  • Re:PS. (Score:3, Informative)

    by bhtooefr (649901) <`gro.rfeoothb' `ta' `rfeoothb'> on Tuesday May 04, 2010 @08:07PM (#32092638) Homepage Journal

    It's called SpeedStep. (OK, it doesn't reduce the CPU usage, but it reduces the CPU clock speed, which is more effective.)

  • A better explanation (Score:5, Informative)

    by Sycraft-fu (314770) on Tuesday May 04, 2010 @08:11PM (#32092668)

    The article kinda glosses over things. So a more detailed explanation of how Intel's turbo boost works:

    As stated, every core has a budget for the maximum heat it can give off, and the maximum power it can use, as well as a max clock speed that it can handle. However, when you look at these things, they aren't all even, one ends up being the limiting factor. So Intel said, ok, we design a chip to always run at a given speed and stay under the thermal and power envelopes. However, if it isn't running at that, we allow for speed increases. It can increase the speed of cores in 133MHz increments. If things go over, it throttles it back down again.

    This can be done no matter how many cores are active, but the less that are active the more it is likely to be able to be. On desktop cores, it isn't a big deal since they usually run fairly near their speed limit anyhow. So you pay see only 1 or 2 max 133MHz increments that can happen. For laptop cores, in particular quad cores, it can be a lot more.

    The Intel i7-720QM runs at 1.6GHz and has 1/1/6/9 turbo boost multipliers. That means with all 4 cores running, it can clock up at most 1 increment, to 1.73GHz. However with only one running, it can go to 2.8GHz, 9 133MHz clocks up. It allows for a processor that would be too fast to reside in the laptop to go in there with some flexibility. A desktop Core i7-930 is 2.8GHz with 1/1/1/2 turbo mode. That means it'll clock up to 2.93GHz with 2-4 cores active, and 3GHz with 1. Much less flexible, since it is already running near it's rated max clock speed.

    Now this is not the same as speed step, which is their technology to down clock the CPUs when they aren't in so much use. Similar idea, but purse based on how hard the CPU is being asked to work, not based on if the system can handle the higher speeds.

    As an aside, I'll call BS on the "Little uses multiple cores." Games these days are heavily going at least dual core, some even more. Reason is, if nothing else, the consoles are that way too. The Xbox 360 has 3 cores, 2 threads each. The PS3 has a weak CPU attached to 7 powerful SPUs. On a platform like that, you learn to do parallel or your games don't look as good. Same knowledge translates to the PC.

    However there are still single core things, hence the turbo boost thing can be real useful. In laptops this is particularly the case. If the i7 quad was limited to 1.6GHz, few people would want it over one of the duals that can be 2.53GHz or more. Just too much loss in MHz to be worth it. However now, it can be the best of all worlds. A slower quad, a faster dual, whatever the apps call for, it handles.

  • by Anonymous Coward on Tuesday May 04, 2010 @08:14PM (#32092692)

    try passive cooling. http://www.vonslatt.com/proj-cc.shtml

  • Re:Huh? (Score:4, Informative)

    by DeadboltX (751907) on Tuesday May 04, 2010 @08:18PM (#32092734)

    The way I understand it (and I could be wrong) is that on a quad core 1.6ghz i7 each core is actually capable of going up to 2.8ghz, although I'm not sure if they are all capable of going to 2.8ghz at the same time. If you run a program that can't take advantage of more than 1 core, and it starts maxing out that core at 100%, the cpu will increase the clock speed of that core, up to 2.8ghz until it isn't maxed out anymore. In order to keep energy consumption and heat down the cpu will also lower the clock speeds of the other cores as needed.

    With older multi-core processors if you had a quad core 1.6ghz and you had a program that could only use 1 core then you would effectively just have a 1.6ghz processor, in which case a dual core 2.8ghz would be way better. With Turbo Boost you can essentially get the best of both worlds.

  • Re:PS. (Score:3, Informative)

    by Animaether (411575) on Tuesday May 04, 2010 @08:33PM (#32092816) Journal

    In the off chance that you're running on Windows;
    http://mion.faireal.net/BES/ [faireal.net]
    ( ugly UI, does the job )

  • by washu_k (1628007) on Tuesday May 04, 2010 @08:40PM (#32092862)
    There are a multitude of aftermarket CPU coolers which are much quieter than the stock ones from Intel or AMD. Some chips can even be run passive with the right heatsink. Take a look at the reviews on http://www.silentpcreview.com/ [silentpcreview.com]
  • by DMalic (1118167) on Tuesday May 04, 2010 @09:24PM (#32093146)
    The third core gives a significant performance benefit over two cores, especially since many games were originally designed for consoles and are badly ported to PCs. Unoptimized performance hogs like Grand Theft Auto demand more cores (and can use them). Just today I saw an article on Anandtech describing significant, unexpected benefits from a slower quad core over a newer, faster dual-core in gaming. http://www.anandtech.com/show/3695/the-clarkdale-experiment-mea-culpa [anandtech.com]
  • Re:Huh? (Score:5, Informative)

    by Gr8Apes (679165) on Tuesday May 04, 2010 @11:42PM (#32093894)

    Intel is better.
    Has been that way for many years now. Yes, it's more expensive.

    Depends on your metrics. If the only thing that matters is pure raw speed out of a single die, Intel does eek out on top, but not by as much as you'd think.

    If you're going for massive multi-processor, multi-core systems, it's AMD.

    If it's power vs performance out of a single die, then it depends - idle or full throttle. Intel for the former, AMD for the latter, depending upon weighting.

    and so on. At least as of the last set of performance benchmarks I read just a few months ago on the topic, meaning they're probably completely out of date by now.

  • Re:Can we get.. (Score:3, Informative)

    by wealthychef (584778) on Tuesday May 04, 2010 @11:43PM (#32093904)
    I like Grand Central Dispatch [wikipedia.org]. Don't shoot me, it's from Apple. But it's open source, so it's good, right? What I like about it is that it relieves a programmer from the burden of choosing the number of threads to run, initializing all the various mutexes, etc. Very nice model. I don't see a big driver for adoption, unfortunately, outside of HPC geeks like yours truly.
  • Re:Can we get.. (Score:4, Informative)

    by ckaminski (82854) <ckaminski@pobo[ ]om ['x.c' in gap]> on Wednesday May 05, 2010 @12:12AM (#32094112) Homepage
    Last I checked, fibers were NOT useful for parallelism. They basically slave off of the thread that created them, and have to be cooperatively shared on that same thread of execution.
  • Re:Can we get.. (Score:5, Informative)

    by Hurricane78 (562437) <deleted&slashdot,org> on Wednesday May 05, 2010 @01:10AM (#32094434)

    Actually, that’s pretty easy to do with Linux right now.
    Just choose any ACPI button (you at least have a power button, often more), and in your /etc/acpi/ directory, modify the scripts so they call “cpufreq-set -f $freq” on the right events. (You may need a state file in your /var/state/ dir, to remember which mode you are in. But you can also toggle a keyboard led that you don’t use much.)

    And this is why I love Linux. If you can think of it, and it’s physically possible... you can do it. :)

    Next: Using the graphics ram that is unused while in 2D mode, as a fast swap/tmpfs/cache. ;)

  • Re:Can we get.. (Score:3, Informative)

    by beelsebob (529313) on Wednesday May 05, 2010 @03:29AM (#32095072)

    How about a small daemon that at intervals re-assigns the running processes to the cores in a balanced way (or one of your choice), and also sets the affinity for new processes. Should be about 30 minutes with any fast language of your choice that can call the appropriate commands.

    The linux scheduler doesn't do this? The OS X one certainly does, it also moves processes from core to core based on which one is getting hot.

  • Re:Huh? (Score:2, Informative)

    by Athanasius (306480) <slashdot.miggy@org> on Wednesday May 05, 2010 @04:05AM (#32095260) Homepage
    This [tomshardware.com] might make things a little clearer for the Intel case. Certainly it gives more detail about how it works (for one thing it's not just a "base speed or Turbo speed" thing, there are multiple boost steps depending on the exact situation).
  • Re:PS. (Score:3, Informative)

    by icebraining (1313345) on Wednesday May 05, 2010 @10:00AM (#32097484) Homepage
  • Re:Huh? (Score:3, Informative)

    by AntiDragon (930097) on Wednesday May 05, 2010 @10:01AM (#32097502)

    Performance on it's own isn't meaningful for everyone. If I'm setting up a server or better yet a data center, performance against cost has to be considered. And that's not just the cost of the hardware but also things like MTBF and power costs.

    I'm not implying that one is better than the other here, but a raw performance comparisson between like-for-like processors is not enough information to make spending decsion with. It may be better value to buy the system with poor performance and spend the savings elsewhere for example.

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