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Core i7-2600K Overclocked: Speed Meets Efficiency

Core i7-2600K Overclocked: Speed Meets Efficiency

Most of Intel's Core i5 and i7 CPUs lock out overclocking enthusiasts, which we hate. But the K-series chips win us back over with insane scalability. Would you believe that cranking the dial on performance doesn't necessarily tank overall efficiency?

Before you buy a new Sandy Bridge-based platform, check out yesterday's news about Intel's recall of its Cougar Point chipsets.

Do you remember the old days when overclocking still was a real challenge? First you had to look around for a suitable processor, such as the Intel Celeron ‘Mendocino’, AMD’s Duron ‘Spitfire’ or the Pentium D 805. Each of them could be taken to clock speeds 50% above their respective stock specifications, but you needed a flexible motherboard, overclocking-friendly memory, and a little luck finding the fastest reliable settings through trial, error, and some patience. Occasionally, dead hardware was the price you paid for flying too close to the sun. Even still, I have to admit that it was always fun, as well.

While this approach technically hasn’t changed, the industry now provides motherboards that were specifically designed for overclocking, and high-speed memory modules that help alleviate the bottlenecks on platforms requiring system/FSB overclocking to reach the fastest processor speeds.

Unfortunately, Intel recently integrated the clock generator of its newest platform into the chipset, which means that P67 Express (Cougar Point) is no longer easily overclockable through base clock-based increases. This affects the PCI Express clock as well, which typically ends in frustration when pushed very far at all. Therefore, everyone with overclocking ambitions on the LGA 1155 platform should go straight for a K-series Core i5/i7 processor. The additional cost compared to regular CPUs is acceptable, and we found that the Sandy Bridge-based Core i5/i7 K-series processors actually introduce a paradigm change.

AMD and Intel have been offering Black Edition and K-series processors for a while, meaning there is nothing new on this end. These products are specifically designed to facilitate overclocking by allowing the user to adjust the clock multiplier directly. Hence, you can reach higher clock speeds without the necessity of dragging the entire platform to critical clock speed levels.

With Intel’s latest 32 nm Core processor generation, code-named Sandy Bridge, these overclocking-oriented processors actually start to make a lot more sense in the mainstream. Thanks to Turbo Boost 2.0 and the chips’ power control unit, which monitors power and temperatures, Sandy Bridge factors out much of the luck/skill that was previously involved in achieving high maximum clock rates, as well as much of the risk previously associated with overclocking. In the case of Sandy Bridge, this means that even beginners can now safely aim at a significant overclock and let the platform do the rest.

In this article we overclock a Core i7-2600K processor using Intel's reference heatsink and fan. Our analysis includes performance and power efficiency, which scales impressively well on Sandy Bridge as you keep increasing clock rates.

Display 74 Comments.
  • 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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