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UPDATE: Core i7: Blazing Fast, O/C Changes

UPDATED: Overclocking Up To 3.80 GHz

The overclocking potential of the Core i7 is similar to that of the Core 2, which is to say, very good. We were able to overclock our Core i7 965 Extreme from 3.20 GHz to 3.60 GHz without raising the core voltage or encountering stability issues.

According to Intel, the Extreme Edition will continue to come with an unlocked multiplier. However, our Intel DX58SO motherboard did not allow us to increase the multiplier beyond the default value of 24 for the Core i7 965 Extreme, so we ended up overclocking by increasing the internal front side bus from 133 to 150 MHz. We set the memory multiplier to 8x, resulting in a CPU clock speed of 3.60 GHz and a memory speed of DDR3-1200.

Our US lab is able to confirm that the Core i7 965 Extreme’s multiplier cannot be increased using Intel’s DX58SO motherboard—it’s capped at 24x and can only be reduced. The only way to overclock this motherboard/processor combination is to enable Turbo Mode, increase the maximum amp/watt limits to an impossibly high number, and configure the maximum Turbo multiplier range for 1, 2, 3, and 4 core operation to your desired overclock setting. In this way, Turbo mode will never hit the maximum thresholds you define and, ideally, never throttle back. We’ll get into Turbo mode more on the next page.

The ASUS Rampage II Extreme board is able to manually adjust multiplier setting upward, however, making a 3.7+ GHz overclock as easy as keying in a 28x setting on that platform. After more extensive testing, our i7 965 Extreme peaked at just over 4 GHz, and our i7 920 sample ran stably at 3.8 GHz using the ASUS board and a mix of multiplier/Bclk/voltage tweaking.

We were only able to push our Core i7 965 Extreme to a stable 3.84 GHz by increasing the core voltage to 1.4125 Volts. Again, this was achieved by increasing the FSB to 160 MHz, giving us a memory frequency of DDR3-1280; we were unable to get our test sample of the Core i7 to run any faster. In our experience, the final retail versions of processors that show up in stores offer much better overclocking potential than the early engineering samples we get for our launch reviews. For our overclocking experiments, we set the Overspeed Protection features to 300 amperes and 300 watts.

Multipliers of the Core i7 Models

ModelMultiplierFSB
Core i7 965 Extremex24133 MHz
Core i7 940x22133 MHz
Core i7 920x20133 MHz

DDR3 Memory Required for the Core i7 920 and 940

FrequencyFSB68
4.00 GHz200DDR3-1200DDR3-1600
3.80 GHz190DDR3-1140DDR3-1520
3.60 GHz180DDR3-1080DDR3-1440
3.40 GHz170DDR3-1020DDR3-1360
3.20 GHz160DDR3-960DDR3-1280
3.00 GHz150DDR3-900DDR3-1200
2.80 GHz140DDR3-840DDR3-1120
2.66 GHz133DDR3-798DDR3-1064
FrequencyFSB68
4.40 GHz200DDR3-1200DDR3-1600
4.18 GHz190DDR3-1140DDR3-1520
3.96 GHz180DDR3-1080DDR3-1440
3.74 GHz170DDR3-1020DDR3-1360
3.52 GHz160DDR3-960DDR3-1280
3.30 GHz150DDR3-900DDR3-1200
3.08 GHz140DDR3-840DDR3-1120
2.93 GHz133DDR3-798DDR3-1064
  • joseph85
    Good article, and may I say Keep up the good work.
    Reply
  • pullmyfoot
    AMD’s HyperTransport protocol can transmit up to 25.6 GB/s at 3.20 GHz.
    You mean Intel don't you? Other than that little mistake, good article
    Reply
  • wh3resmycar
    hmm, question. once this nehalems come out. will we ever see a dieshrunk c2q again after the penryns? im expecting the price of this procs along with the mobo and ram to be too far off from my budget. or
    Reply
  • skywalker9952
    One of the first side effects of Intel's domination of the CPU market is beginning to show. Since they don't have to compete with AMD in any market segment the i7 occupies, they have limited (significant) overclocking to only extreme models.

    RIP AMD.
    May Abu Dhabi restore you to life soon so we don't have to suffer through more Intel ripoffs.
    Reply
  • sonar610
    "The fastest Core i7, the 965 Extreme, is more than 2.6 times as fast as AMD’s current flagship CPU, the Phenom X4 9550 BE."
    This seems like an editing mistake maybe it should be 9950BE.
    Reply
  • cryogenic
    Core i7 is a great CPU, the article is not. I can't believe after all this time you still stack overclocked CPUs with unoverclocked ones. It's great to find out the overclocking potential of Nehalem but, at least include some overclocked Penryns in there too, to see how overclocked Nehalem stacks agains OTHER overclocked CPUs, because it's fairly evident that and overclocked new gen CPU will stack well with older non overclocked ones.

    Reply
  • joseph85
    CryogenicCore i7 is a great CPU, the article is not. I can't believe after all this time you still stack overclocked CPUs with unoverclocked ones. It's great to find out the overclocking potential of Nehalem but, at least include some overclocked Penryns in there too, to see how overclocked Nehalem stacks agains OTHER overclocked CPUs, because it's fairly evident that and overclocked new gen CPU will stack well with older non overclocked ones.If it's evident then who cares?
    Reply
  • fender22
    skywalker9952One of the first side effects of Intel's domination of the CPU market is beginning to show. Since they don't have to compete with AMD in any market segment the i7 occupies, they have limited (significant) overclocking http://en.wikipedia.org/wiki/Overclocking to only extreme models.RIP AMD. May Abu Dhabi restore you to life soon so we don't have to suffer through more Intel ripoffs.
    My thoughts exactly... I wonder if there will be some sort of resistance to this sort of thing... It's like buying a car, you can do whatever you want to it (within the limits of the law) to make it as fast as you want. Sure, you may void your factory warranty, but it's your deal. You don't see car companies making it impossible for you to do what you want to their cars so you have to buy their expensive high end just to get your kicks... (not a perfect comparison, but it works)

    I dunno, it's just pretty weak. And they are just taking advantage of the situation...
    Reply
  • cangelini
    sonar610"The fastest Core i7, the 965 Extreme, is more than 2.6 times as fast as AMD’s current flagship CPU, the Phenom X4 9550 BE." This seems like an editing mistake maybe it should be 9950BE.
    Fixed, thanks!
    Reply
  • onearmedscissorb
    Aside from the all too prevalent and potentially misleading typos, which someone needed to get a handle on as of months ago, I must say that the overall quality of this article is MUCH better than pretty much anything I can remember of the last few months. It's actually informative and thought out, rather than being a mess of assumptions that many people reading already know better than.

    Keep it up, and maybe I'll pay attention to this site like I used to.

    But just for the record, I don't believe that it's particularly appropriate to use the overall average performance percentages as a basis for comparison between the "speed" of Core 2 vs. Core i7. Obviously, most people are going to be interested in the difference with games, where it's likely to be pretty minimal. But here and there, you have something like the 55% WinRAR difference pretty much skewing what otherwise would have been an accurate depiction of average expectations across the board.
    Reply