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Conclusion: Overclocking Becomes Efficient

Core i7-2600K Overclocked: Speed Meets Efficiency

This article doesn’t set out to look at the highest clock rate you can achieve on a Sandy Bridge-based processor. For that, we'd want to use more aggressive cooling, higher voltages, and generally throw the entire efficiency story out the window completely. At the high end, existing BIOSes support 5700 MHz through a 57x multiplier and a bit more through modest BCLK increases. This is the top end for now, though Intel's engineers have told us that they intend to edge the multiplier limits up slightly.

Practically, though, you should be able to reach anywhere between ~4.5 and roughly 5 GHz on air cooling with all Core K-series processors based on the 32 nm Sandy Bridge architecture.

There are three conclusions we can draw from this article:

1. Sandy Bridge overclocks well

It certainly didn’t take this article to find that Sandy Bridge overclocks very well, at least as long as we’re talking about the K-series processors in Intel's Core i5/i7 portfolio. Going beyond 4 GHz is easily possible, even without a voltage increase, and our processor sample scaled reliably all the way up to 5 GHz on the standard Intel cooler.

2. Overclocking no longer trades efficiency for performance

While all previous processor generations caused an increase in power consumption that was always more substantial than the added performance  (especially at higher, more difficultly-achieved frequencies), Sandy Bridge is the first processor architecture where clock speed and power consumption scale almost linearly.

Effectively, this means that your overclocking attempts are neutral to total power consumption. If you speed up the processor, you will consume more power, but the workload will terminate quicker, which in the end saves time. Stock speeds and the overclocking settings both require a very similar amount of total power. This is made possible through persistently low idle power consumption paired with great performance per clock.

3. Overclocking can be fool-proof now

There is a paradigm change going on, as performance is no longer strictly defined by clock rate, but by the defined processor power limit. Once you understand that this power limit is a neat way of keeping a K-series Core i5/i7 processor within a thermal envelope, you understand that overclocking governed by the power control unit is like adding a safety net to your overclocked setup. Provided that your CPU cooler is aligned to your selected power limit, you can crank up clock speeds and you will typically get a very reliable configuration that automatically decreases clock speeds once it fully utilizes the defined power limit.

Intel’s next architecture step will be a shrink of Sandy Bridge into 22 nm, code named Ivy Bridge. We don’t expect it to introduce fundamental architectural changes, but I’m definitely curious if Intel can continue to improve power efficiency. Will the 22 nm Haswell architecture, to follow Ivy Bridge, possibly ignite a new clock speed race because it might make sense again from an efficiency standpoint? What’s your opinion?

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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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