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Power Consumption

Intel’s Mobile Core i5 And Core i3: Arrandale Is For The Rest Of Us
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The Core i5-540M is a 35W processor, whereas Intel’s Core 2 Duo P8700 is a 25W part. Thus, it’s hardly a surprise to see the Montevina platform using less power in Prime95 than the newer Calpella design (note that these numbers were taken with no battery installed).

In fact, we certainly expected Arrandale to use more power under load based on our previous experiences with Core i7-920XM. In that story, we saw Turbo Boost and Hyper-Threading maximizing performance, depending on workload, at the expense of power consumption, whereas Core 2 Quad (or Duo, in this case) is unable to deliver a dynamic performance story.

The match-up gets much closer at idle. Although the i5-540M sports a higher TDP and two-die package, it also employs a two-chip platform and power gating to minimize the consumption of unused resources.

However, these min./max. figures don’t tell the whole story, so we also recorded a PCMark Vantage run on each notebook and charted out power use at two second intervals.

Although the 35W Core i5-540M clearly uses more power under load, it also dips well under the Core 2 Duo P8700 during Vantage’s down-time, despite the load/idle numbers above.

When you even out all of the peaks and valleys, you get 32.9W average power consumption for the Arrandale processor and 31.7W for the Penryn-based Core 2 Duo. When we factor in the fact that the Core i5-540M system finished the test 2:26 faster than the Core 2 Duo, dropping back to idle as the other machine completed its workload, we’re able to conclude that there’s finally evidence of Nehalem-based processors outdoing Core 2 when it comes to overall power consumption. The performance story tells itself. Arrandale is clearly the quicker chip, too.

This is something we’ve been waiting on for a while now. First, we heard about power gating, which would shut down unused processing cores almost completely. Then there was the inclusion of PCI Express and memory control with Lynnfield. Adding Windows 7 to the mix was supposed to optimize power usage further. But each step along the way, we saw the Nehalem design using more power than we had expected. “Wait for Arrandale, wait for Arrandale, wait for Arrandale,” was what we kept hearing. Now that Arrandale is upon us, we see the wait was worthwhile. The two-chip platform architecture, heavy integration, and shift to 32nm manufacturing means it’s now possible to get significantly better performance from a dual-core, four-thread CPU at lower overall power use than a comparably-equipped dual-core notebook based on Core 2.

Display all 20 comments.
  • 3 Hide
    burnley14 , January 4, 2010 5:34 AM
    Well played, Intel. You've been knocking it out of the park lately, keep up the good work.
  • 4 Hide
    Anonymous , January 4, 2010 5:39 AM
    I'm looking forward to getting an HP laptop with the Arrandale Core i5 processor in the near future.
  • 2 Hide
    Anonymous , January 4, 2010 10:53 AM
    It's going to be interesting to see the performance/battery time of the LM and UM processors as I'm in the market for a thin-and-light myself.

    Performance is good but I'm hoping for a viable update to the CULV offerings of yesterday.
  • 1 Hide
    Computer_Lots , January 4, 2010 1:32 PM
    Looks like there are finally some replacements for the Atom, at least in efficiency anyway. Too bad the price is currently too high for the UM versions of these processors to make their way into netbooks. I would guess that even the i5-520UM would destroy the Atom in every benchmark, except maybe power consumption.
  • 2 Hide
    HansVonOhain , January 4, 2010 10:22 PM
    C2D was one of the longest living platforms. But newer tech will replace slower processors.

    Keep it up intel. I do hope that AMD will release some new chips that will be able to compete with intel offerings.
  • 0 Hide
    jasperjones , January 4, 2010 10:46 PM
    ^^^ true that. arrandale will further diminish AMD's role in the mobile processor market. and there's nothing coming up before may.
  • 0 Hide
    Luscious , January 5, 2010 1:23 AM
    Chris, the dv4 series from HP has a 12-cell extended battery available as well rated for 94Wh 2.2A. Once HP makes the transition to Arrandale, all else being same, you can expect the dv4 to hit 8-10 hours easy.
  • 0 Hide
    cangelini , January 5, 2010 1:33 AM
    Thanks for the tip Lucious. I didn't have the higher-capacity battery available to test, but I'd absolutely love to see 8-10 hrs. real-world from an Arrandale-based machine.
  • 1 Hide
    Reynod , January 6, 2010 10:07 AM
    Good bye NVidia ...

    That chops them completely out of the mobile graphics market for the masses ... Intel will pay the RIGHT OEM's some "adjustment" just to make sure their "Strategy" is right to ensure AMD's mobile market is thin and restricted to the backwaters of Bejjing.

  • -1 Hide
    spydercanopus , January 6, 2010 1:24 PM
    Wish you would have compared it to Intel Extreme Graphics 2 or something.
  • -2 Hide
    spydercanopus , January 6, 2010 1:26 PM
    These comparisons aren't very useful. Was really curious how it stacks up against other competing integrated graphics.
  • 0 Hide
    spydercanopus , January 6, 2010 1:27 PM
    Like... what is the Vista / 7 Aero and Gaming graphics score?
  • 1 Hide
    cangelini , January 6, 2010 1:33 PM
    spydercanopusThese comparisons aren't very useful. Was really curious how it stacks up against other competing integrated graphics.


    Have a look at Page 8, where HD Graphics is compared to the previous-generation GMA in Vantage and WoW. You're not going to get much else out of this, to be honest...
  • 1 Hide
    Anonymous , January 7, 2010 3:26 PM
    Ok so we get 20% improvement over a 2.53GHz C2D but what about the fact that C2D goes to 3.06 GHz and 3.33GHz in extreme edition, but the best arrandale is only 2.66Ghz?

    Also the integrated graphics can barely match the 9400m that is 1-2 years old.

    The battery life is the same or worse...

    What is so great about this chip?

    Personally I'm not at all impressed and find it a step side ways or even backwards.
  • 0 Hide
    xanxaz , January 27, 2010 9:36 PM
    ASUS EFI? can it load the apple one?
  • 2 Hide
    Anonymous , February 5, 2010 5:03 AM
    Just because the older C2D's have higher clocks doesn't necessarily mean they are better. Advances in the micro-architecture sometimes leave clock freqs irrelevant. An i7 920 @ 2.66 will beat a Core 2 Extreme QX9770 @ 3.2. But to be sure I guess we will have to see the highest end Arrendale vs highest end C2D.

    The integrated graphics do suck, but at least now we have a choice in some laptops where we can switch from the integrated to dedicated, saving battery life when needed and boosting performance where needed. It adds flexibility basically, I'm sure Intel was aiming more for that rather than performance in 3D games.

    What I really want to see is the ULV versions of this chip. I'm hoping whenever they start coming out, it'll push down the prices of older Ultra-Portable laptops around the 12-14" sizes. Certain ones with the C2D SU7300 and 4GB of RAM can be found for around $550 today. If these prices go down far enough, netbookks will be obsolete in my mind.
  • 0 Hide
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  • -1 Hide
    Anonymous , April 19, 2010 8:11 PM
    Interesting that no mention was made of how Apple has been building Core 2 Duo notebooks that will play 4 movies on a single battery charge, while the i5's and i7's are great, I don't think Intel's Duos can be blamed for your notebook's barely being able to play a single movie. (note Apple is now making notebooks with the i5 and i7 processors which also can run all major operating systems)
  • 0 Hide
    Anonymous , May 12, 2010 5:47 PM
    Hey, Did you know these Arrandale CPUs are starting to pop-up already? I've noticed this review for the Core i5-520UM today, google says it's new: http://www.netbooklive.net/intel-core-i5-520um-benchmarked-on-asus-ul30jt-3493/ . Hopefully It's ok to post links in here, as they are related and help the readers of this post.
  • 0 Hide
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