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Turbo Boost 2.0 And The PCU Manage Overclocking

Core i7-2600K Overclocked: Speed Meets Efficiency

Intel's Core i7-2600K and the Core i5-2500K processors feature unlocked clock multiplier adjustments, DDR3 memory ratios of up to 2133 MT/s, and power/current limits that can be disabled entirely. Flexible P67-based motherboards with broad overclocking options provide BIOS or UEFI items to alter ceilings in place on non-K-series parts. That distinction is pretty important, because other chips centering on Sandy Bridge are artificially capped by Intel. The beauty of Turbo Boost and Intel’s so-called Power Control Unit (PCU) in particular is that these functions offer their services at stock speeds, as well as in overclocked scenarios.

Effectively this means that the processor’s built-in performance optimization features will also speed up the system, even if it’s already overclocked. Turbo Boost will add up to four speed bins as long as the thermal envelope allows. A 4 GHz base clock and up to four clock speed increments (+400 MHz)? This isn’t a problem if the power limits allow, and as long there is sufficient processor voltage to sustain stable operation. This would be the safer, more mainstream way to overclock, since you're targeting a lower frequency and letting the platform control increases based on available headroom.

However, you can also consider changing the specific number bins Turbo Boost uses to increase clock rate, and you can also alter the power limit on K-series processors. The default values are +1 speed bins for four active cores, +2 for three cores, +3 for two cores, and 4 speed bins up for a single core. These values can be adjusted as you wish, but keep in mind that more significant clock speed jumps might cause issues for the voltage regulators.

The power control unit will mostly prevent your system from overheating and crashing when overclocked, as long as you select a reasonable power limit and as long as your processor's cooler is capable of dissipating the resulting thermal energy. It is of course easy to outsmart the power control unit by selecting settings that may just be over the top, for example, a power limit way beyond reason or beyond the capabilities of your CPU cooler. In such a case, the system will most likely crash the old fashioned way.

However, Turbo Boost on K-series processors can be set rather granularly and the power management allows us to comfortably increase processor wattage and current tolerances. You chart the course. Intel's architecture effectively provides the auto pilot. Let’s see how well this works in terms of performance and efficiency.

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  • 7 Hide
    _Pez_ , February 1, 2011 3:16 AM
    hmm There is not much to say it is powerfull and energy efficient even overclocked. good work Intel. and Hard work for AMD.
  • -6 Hide
    _Pez_ , February 1, 2011 3:17 AM
    _Pez_hmm There is not much to say The CPU is powerful and energy efficient even overclocked. good work Intel. and Hard work for AMD.

  • -1 Hide
    dogman_1234 , February 1, 2011 3:25 AM
    Is it good to know that overclocking requires no effort at all? I always thought OC'ing was enthusiast based for its lever of difficulty. Now, anyone can overclock like they can spread butter on toast.
  • 2 Hide
    jprahman , February 1, 2011 3:34 AM
    Very nice, Sandy Bridge keeps looking pretty good.....except for the chipset issues :( . I have to say though, these overclocking results look quite impressive. Unfortunately Intel had to put training wheels so we won't be seeing any extreme overclocks. I thought it would have been pretty cool to see how high someone could push a Sandy Bridge CPU, (6GHz? 7GHz? 8GHz?), unfortunately with the 57x multiplier cap that won't likely be happening.
  • 1 Hide
    slothy89 , February 1, 2011 3:40 AM
    And to think everyone was complaining when Intel announced Sandy was going to have limited OC abilities.. Only limited in that the BCLK would be virtually locked, and for approx $15 to $30 more (2500 + 2600 up to K series) you can get a highly OC-able chip.

    Going from 3.4 to 4.8+ GHz on stock air has until now been unheard of.. Kudos to Intel for changing the way we look at CPUs. No doubt without this integrated clock generator, amoung other things, these insane OCs would be near impossible no matter how small the manufacturing process.

    Just have to wait for them to fix the Sata2 Controller now and Sandy will be back in form!

    AMD, good luck with Bulldozer.. Maybe you should turn your GPUs into CPUs.. lol
  • 3 Hide
    joytech22 , February 1, 2011 3:54 AM
    If AMD doesn't release their new CPU's around the same time Intel fixes their Sata2 controllers then I'm done waiting. The only reason that I didn't do it already is because today I read that article about the Sata Bug, this thursday was going to be my upgrade day.
  • 1 Hide
    aznshinobi , February 1, 2011 4:24 AM
    Why do we all think that it's just the job of Intel? I mean granted they did make the SB series (and I'm very impressed) but 32nm production has something to do with the overclocking as well. I think AM3+ will replicate the same overclocking ability. just IMO.
  • 2 Hide
    touchdowntexas13 , February 1, 2011 4:36 AM
    Impressive. Unfortunately I'm not due for a pc upgrade for a long time seeing as how I just built a core i5 machine about 5 months ago. Should the SATA issues get fixed, I think I will definitely recommend the Sandy Bridge platform to my brother who goes to college next year. Then maybe I will be ready for an upgrade when Ivy Bridge comes out...
  • 1 Hide
    jestersage , February 1, 2011 4:49 AM
    The clockspeed race seems very possible again. At 22nm, 10ghz may just be 4-5 years away. AMD will definitely need to have some form of differentiation (much like the integrated memory controller that propelled them to distinction almost a decade ago) if they are going to catch up but cannot compete with clockspeed (again). Maybe they can capitalize on one of Intel's 'flaws' and incorporate dedicated silicon for video on any platform combination instead of having it turned off when you plug in a dedicated video card. Should be named another Hybrid-something IMO.
  • 2 Hide
    jonnyfour , February 1, 2011 5:17 AM
    Am I crazy? My Intel Core i7 2600k does not have the Huge cooler I keep seeing everywhere. Did I get a fake from Frys?
  • 2 Hide
    PreferLinux , February 1, 2011 5:22 AM
    What temperatures???
  • 1 Hide
    hardcore_gamer , February 1, 2011 5:23 AM
    What is the maximum clock speed for regular use ?
  • 0 Hide
    ddrhazy , February 1, 2011 5:47 AM
    Hope the sandy bridge fix comes quick so I can upgrade. AMD is just out of the game completely and has no way of competing with Intel in the next half year.
  • 2 Hide
    Anonymous , February 1, 2011 7:03 AM
    AFAIK with Boxed-CPUs you don't get the "Tower-Cooler" ...
    There are many discussions in german forums about this behaviour because Intel
    distributss testsamples with the tower-cooler and the boxed-version with normal flat-cooler
  • 1 Hide
    dirtmountain , February 1, 2011 7:08 AM
  • 1 Hide
    Anonymous , February 1, 2011 7:40 AM
    Intel did make a very good processor and thanks to them, over clocking is safe and easy for noobs.
  • 2 Hide
    i_am_aronman , February 1, 2011 7:58 AM
    ddrhazyHope the sandy bridge fix comes quick so I can upgrade. AMD is just out of the game completely and has no way of competing with Intel in the next half year.

    For some reason i am thinking that AMD is having SOME effect on Intel based on the pricing for the new products Intel pushed out. I think AMD has something with bulldozer and i am waiting on it. I do wish AMD would hurry up and release their products though.
  • 2 Hide
    aaron88_7 , February 1, 2011 8:08 AM
    I'm just curious how the LGA 2011 based chips will perform, I mean if the "midrange" chips can easily hit 4.5ghz what will the "enthusiast" chips be clocking at? Or perhaps similar clocking abilities but just with more cores? I'd hope the enthusiast chips will be able to hit 5ghz as easily as these can hit 4.5.

    Still gotta get myself a new cooler and see what my 2600k can clock to!
  • 8 Hide
    aapocketz , February 1, 2011 10:54 AM
    Am I crazy? My Intel Core i7 2600k does not have the Huge cooler I keep seeing everywhere. Did I get a fake from Frys?

    No, unfortunately you are quite sane. Look at the unboxing videos on youtube

    you got the one they ship to normal consumers.

    Tomshardware gets the cherry picked samples that intel sends them for free to test, and they just use the aftermarket cooler that Intel sent them.

    from the article:
    standard Intel cooler. ]our processor sample scaled reliably all the way up to 5 GHz on the standard Intel cooler.

    What is "standard"? that is not the cooler you get in the box. It is not spelled out how much it costs, or even lists it as a separate item on the test setup configuration page. Most reasonable people would think that cooler is what they would get in the box with the processor, or expect the same overclocking results on the actual stock box cpu cooler that comes with the 2600K.

    according to this webpage:

    The cooler itself is an optional cooler called the XTS100H. Its an aftermarket part and is $63 shipped at newegg.

    tomshardware needs to clearly list this in their article.

    its extra confusing since most websites selling the 2600K (like newegg) don't show what you get in the box, which is unusual for newegg which is usually very good about product photos. Conspiracy?
  • 2 Hide
    Ubrales , February 1, 2011 11:25 AM
    Great article; great information!The 'K' processors offer new possibilities to overclockers!
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