Battery Life - Technically, No Better

Now it's time to talk about battery life. Let me run down the tests real quick. This is a combination of the tests Jarred runs in our standard notebook/netbook reviews and the tests I run in my Mac reviews. WiFi was always enabled and connected to an access point 20 feet away. The screen brightness was set to 100 nits and Windows 7 was configured to use its Power Saver battery profile.

The idle test is exactly what you think it is. The notebook just sits at the Windows 7 desktop with no screensaver active until it runs out of battery power. This is a good indication of the best battery life you'll get out of the notebook (e.g. just typing in a text document).

The light web browsing test comes from our Mac reviews and cycles through a series of web pages, pausing on each one for 20 seconds before going on to the next one. There are no flash ads on the web pages. This is the lightest load you'd see when browsing the web. A playlist of MP3s loops in the background.

The average web browsing test also comes from our Mac reviews and cycles through a series of web pages, pausing on each one for 20 seconds before going on to the next one. Each page has between 1 and 4 flash ads on it and there are three concurrent IE8 windows open, each doing the same thing. A playlist of MP3s loops in the background.

The heavy web browsing test opens four tabs in IE8, each heavily loaded with flash ads. The tabs stay open for a short period of time before the cache is cleared and the browser is closed. The system sits at the desktop for a short duration before launching IE8 once more and opening the same four tabs. The test repeats until the battery is drained. This should be close to the worst case battery life while browsing the web.

Our video playback test loops a 720p x264 movie in Media Player Classic Home Cinema x64 until the battery dies. The player uses any GPU acceleration present in the system.

Finally, the heavy downloading/multitasking test mixes a bunch of these tests together. The average web browsing test runs while a 480p XviD movie plays and while a download script executes and downloads files at a constant 500KB/s from a server.

I kept as many variables constant as possible between the two systems. Both are configured with the same amount of memory, with the same HDD and are set to the same brightness. Both systems are normalized to the same battery capacity to produce an apples-to-apples comparison of battery life.

And now, the results:

Battery Test Core 2 Duo P8700 (2.53GHz) Core i5-540M (2.53GHz) Arrandale Advantage
Idle 216 minutes 215 minutes None
Light Web Browsing 177 minutes 188 minutes +6%
Average Web Browsing 177 minutes 186 minutes +5%
Heavy Web Browsing 174 minutes 176 minutes None
Video Playback (x264) 132 minutes 134 minutes None
Heavy Downloading/Multitasking 144 minutes 147 minutes None

 

For the most part there's actually no improvement in battery life due to Arrandale. There are a couple of instances where we see a 5 or 6% increase in staying power but these two platforms are basically equal. That's great when you consider how much faster Arrandale is than its predecessor, but it's not great when you remember that we're talking about a fully power gated 32nm processor here.

If we look at our desktop Clarkdale results we see that idle power for Intel's 32nm part isn't very good. It's actually worse than the 45nm Lynnfield platform from earlier this year. Intel confirmed that there is a lot of optimization that has to happen with Arrandale. It looks like there are some silicon level tweaks that are on the roadmap to be implemented but we won't see them until the middle of 2010. That means while the first Arrandale notebooks won't offer any more battery life than their predecessors, the second wave of Arrandale should fix that.

There's also one more thing to worry about. All of our battery life tests are carefully constructed to make sure they execute the same amount of work on all systems. Twenty seconds takes the same amount of time regardless of how fast your CPU is. As we've already seen, Arrandale is nearly 20% faster than the current mobile Core 2 Duo at the same clock speed. It is possible for you to get much worse battery life out of Arrandale simply by doing a lot more work. Intel estimates that if we were to loop Cinebench over and over again we'd see about 30% worse battery life on Arrandale vs. the previous generation mobile Core 2. The reason being that Arrandale would be much faster, but draw more power. It would be doing more work over the course of the test.

For an end user all this means is that you can do things like encode videos faster on Arrandale than you could before. You can either do the same amount of encoding, faster, without hurting battery life, or you can do more encoding, in the same amount of time, while reducing battery life. Just something to be aware of as Arrandale notebooks have the ability to be just as power efficient as existing notebooks, but can easily be more power hungry if you let them.

Performance - A Huge Improvement Final Words
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  • MonkeyPaw - Monday, January 04, 2010 - link

    Personally, I'm disappointed with the "unchanged" battery life. The reality is, most IGP-based notebooks don't need to be faster to most people. A few friends of mine recently bought notebooks, and they have what I call average requirements: email, browser, iTunes, office, photo management. My advice to them was that anything they buy today will be more than fast enough for their needs (they were currently running outdated machines), and that their decision should be based on things like battery life and bonus features. Even my own notebook purchase was based less on total processing power and more on price, then battery life.

    I think Intel had it backwards. Start by improving battery life, then slowly improve performance. That may have been their plan, but it looks like 32nm has a ways to go for them before that can happen.
    Reply
  • JarredWalton - Monday, January 04, 2010 - link

    I would expect the LV versions to be competitive, but it wouldn't surprise me if the initial 32nm parts are not where they would like in terms of power use. The rev 2 of Arrandale will hopefully address that shortcoming. Reply
  • secretanchitman - Monday, January 04, 2010 - link

    thats the thing though - who knows what apple is going to do now, since they currently use ion/9400m in the macbooks/macbook pros. they do use intel + discrete ati in the current imacs, yet the lowest end imac has a 9400 in it. the problem with arrandale is that it has the gpu integrated on, and traditionally...intel integrated graphics suck compared to nvidia and ati gpus.

    im hoping that intel made special versions of arrandale without the built in gpu, or they are able to turn it off, and use separate graphics instead. lets be honest, the 9400m is much better than anything intel offers now.
    Reply
  • taltamir - Thursday, February 04, 2010 - link

    what does it matter? apple can't run games anyways... neither can any laptop.
    The difference between intel and nvidia/ati is that a laptop with nvidia/ati can get playable FPS on the absolute LOWEST settings which look like crap. the intel can NOT get playable FPS, period.
    Either would be a horrid experience for a gamer... get a desktop if you want to game.
    Reply
  • filotti - Tuesday, January 05, 2010 - link

    Actually, the article says that the performance of the integrated GPU is equal to the performance of the 790GX IGP. This means that it should be equivalent to the 9400m too. Reply
  • mino - Saturday, January 09, 2010 - link

    Raw performance? Probably comparable to 785G in 3D benchmarketing.

    Drivers to be able to use the performance. Non existent.

    This is pretty much a beefed up HD4500. Nothing less, nothing more.
    Reply
  • marc1000 - Monday, January 04, 2010 - link

    The desktop versions have a 16xPCIe slot, so I believe it IS possible to pair the mobile versions with discrete grapchis too. Not that manufacturers will be that much interested in doing so. After all, it seems that Intel aimed for the same level of performance that 9400 has, so Apple would not have reasons to go "non-Intel". I guess this is the primary reason why they made the GPU perform exactly at this level. It's the "good enough" philosophy. Reply
  • Penti - Tuesday, January 05, 2010 - link

    Of course you can, HM/QM/QS57 supports switchable graphics too and has x16 or the same 16 (maybe) lanes on-die as the desktop parts for discrete graphics. It also has 8 lanes on the chipset. Apple, HP, Dell, Fujitsu etc will be interested in more high-end business models and consumer products. Reply

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