Battery Life: All Day Computing

AMD makes a point of their mobile offerings (A/C/E-series APUs) all offering “all day computing”, with a note that “all day” is defined as eight hours or more. While that’s easy to do with a gigantic battery, doing so with the typical 48/56Wh batteries in mainstream laptops is a lot more difficult. One of their test notebooks apparently manages around 10.5 hours (best-case) with a 62Wh battery, compared to 6.5 hours for a similar Core i5-2410M laptop. Without specifics on all the settings, we’ll just say that our results for “similar” laptops don’t show nearly the disparity AMD achieved, but the important point is that AMD is finally competitive in battery life.

We ran our usual series of battery life tests, with the LCDs set for ~100 nits (70% brightness for the Llano laptop). We shut off WiFi for the idle test and mute audio; the Internet test is run over WiFi and repeatedly loads four tabs of content every minute, again with audio muted; finally, the H.264 playback result is done with a set of earbuds connected and WiFi disabled. Here’s how the Llano laptop stacks up to some recently reviewed laptops—you can compare Llano with other laptops in Mobile Bench.

Battery Life - Idle

Battery Life - Internet

Battery Life - H.264 Playback

Starting with pure battery life, only three laptops consistently offer longer battery life than the Llano system: the ASUS U41JF, MSI’s X370, and the quad-core Sandy Bridge notebook. Also, the ASUS K53E boasts better battery life in the H.264 playback test, which for whatever reason is a test where SNB has proved particularly potent. Intel’s DXVA decode may be efficient, but it's also possible it's doing less work; we're running the test again with all of AMD's video enhancement features turned off. [Update: I retested with all the AMD video enhancement features disabled, and battery life didn't change, so Intel is simply more efficient at H.264 decoding with SNB.]

Back to the discussion of battery life: all three of the laptops that beat Llano have the advantage of slightly to moderately higher battery capacities, so the comparison isn’t entirely fair. Let’s level the playing field by looking at relative battery life.

Relative Battery Life - Idle

Relative Battery Life - Internet

Relative Battery Life - H.264

Rather amazing is that Llano actually rises to the top of the charts in the Idle test, and it’s only slightly behind the competition in the other two tests. Considering the X370 is equipped with an E-350 APU, the fact that Llano is even close is surprising. While we should note that the X370 wasn’t the most efficient of the E-350 laptops we’ve tested, we also need to point out that the 13.3” LCD is a lot closer to the 14” panel in the Llano notebook than the 11.6” panels used in the Sony YB and HP dm1z. The dual-core SNB notebook still leads in the H.264 test, and considering it has a 15.6” panel we’d say that relative battery life is very similar between the two.

We also want to talk about AMD’s claims of “all day battery life”. If we accept their definition of 8+ hours, the test laptop doesn’t actually hit that mark in our idle test. We did run the same test again at 40% LCD brightness (around 60 nits) and managed eight hours exactly, but that’s in an absolutely best-case test. For Internet surfing, which represents a more useful metric, the best way to get 8+ hours is demonstrated by ASUS’ U41JF: stuff in a higher capacity battery!

Rounding out the battery life discussion, we also tested battery life while looping 3DMark06 at native resolution (1366x768). This represents a reasonable 3D gaming scenario, and Llano still managed a reasonable 161 minutes. Considering graphics performance is a healthy step up from what Intel’s HD 3000 offers and that AMD manages double the battery life under gaming situations compared to the K53E, mobile gaming is clearly a win.

Overall, for the first time in a long time, AMD is able to offer battery life that competes with and even exceeds what Intel offers with their current mainstream offerings. There are of course a bunch of lower power Intel CPUs we could discuss, but looking at the 35W TDP parts the combination of 32nm and power gating has brought AMD back into the discussion. Even more interesting is that you should be able to get something like our test laptop for $600, possibly less, compared to dual-core SNB i5 laptops that start at $700. But then, perhaps Core i5 isn’t the best comparison for quad-core Llano, despite what AMD might like to say? Let’s move on to general performance and gaming discussions before we decide which mobile part is the “best”.

AMD’s Llano Mobile Test Platform Application Performance, Round One: PCMark 7
Comments Locked


View All Comments

  • Brian23 - Tuesday, June 14, 2011 - link


    Based on the benchmarks you've posted, It's not very clear to me how this CPU performs in "real world" CPU usage. Perhaps you have it covered with one of your synthetic benchmarks, but by looking at the names, it's not clear which ones stress the integer vs floating point portions of the processor.

    IMO, a test I'd REALLY like to see is how this APU compares in a compile benchmark against a C2D 8400 and a i3 380M. Those are both common CPUs that can be used to compare against other benchmarks.

    Could you compile something like Chrome or Firefox on this system and a couple others and update the review?

    Thanks! I appreciate the work you guys do!
  • ET - Tuesday, June 14, 2011 - link

    PCMark tests common applications. You can read more details here:

    While I would find a compilation benchmark interesting, are you suggesting that this will be more "real world"? How many people would do that compared to browsing, video, gaming? Probably not a lot.
  • Brian23 - Tuesday, June 14, 2011 - link

    Thanks for the link. I was looking for something that described what the synthetic benchmarks mean.

    As for "real world," it really depends from one user to the next. What I was really trying to say is that no-one buys a PC just to run benchmarks. Obviously the benchmark companies try to make their benchmarks simulate real world scenarios, but there's no way they can truly simulate a given person's exact workload because it's going to be different from someone else's workload.

    If we're going down the synthetic benchmark path, what I'd like to see is a set of benchmarks that specifically stresses one aspect of a system. (i.e. integer unit or FPU.) That way you can compare processor differences directly without worrying about how other aspects of the system affect what you're looking at. In the case of this review, I was looking at the Computation benchmark listed. After reading the whitepaper, I found out that benchmark is stressing both the CPU and the GPU, so it's not really telling me just about the CPU which is the part I'm interested in.

    Switching gears to actual real world tests, seeing a compile will tell me what I'm interested in: CPU performance. Like you said, most people aren't going to be doing this, but it's interesting because it will truly test just the CPU.
  • JarredWalton - Tuesday, June 14, 2011 - link

    Hi Brian,

    I haven't looked into compiling code in a while, but can you give me a quick link to a recommended (free) Windows compiler for Chrome? I can then run that on all the laptops and add it to my benchmark list. I would venture to say that an SSD will prove more important than the CPU on compiling, though.
  • Brian23 - Tuesday, June 14, 2011 - link


    This link is a user's quick how-to for compiling chrome:

    This is the official chrome build instructions:

    Both use Visual Studio Express which is free.

    I really appreciate this extra work. :-)
  • krumme - Tuesday, June 14, 2011 - link

    The first links at the top is sponsored
    3 times exactly the same i7 + 460 ! ROFL
    Then 1 i7 with a 540
    Damn - looks funny, but at least it not 1024 *768 like the preview, but the most relevant resolution for the market - thank you for that
  • Shadowmaster625 - Tuesday, June 14, 2011 - link

    Man what is it with this dumb yuppie nonsense. No I dont want to save $200 because I dont actually work for my money. Hell, if you're even reading this site then it is highly likely that the two places you want more performance from your notebook is games and internet battery life. All this preening about intel's crippled cpu being 50% faster dont mean jack because ... well its a crippled cpu. It cant play games yet it has a stupid igp. Why get all yuppity about such an obvious design failure, so much so that you'd be willing to sneeze at a $200 savings like it means nothing. It actually means something to people who work for a living. Most people just dont need the extra 50% cpu speed from a notebook. But having a game that runs actually does mean something tangible.
  • madseven7 - Tuesday, June 14, 2011 - link

    I'm not sure why people think this is such a crappy cpu. Am I missing something? Wasn't the Llano APU that was tested the lowest of the A8 series with DDR 1333? Doesn't it give up 500MHz-800MHz to the SB notebooks that were tested? Wouldn't the A8 3530mx perform much better? I for one would love to see a review of the A8 3530mx personally.
  • ET - Tuesday, June 14, 2011 - link

    Good comment. This is the highest end 35W CPU, but not the highest end Llano. So it gets commended for battery life but not performance. It will be interesting to see the A8-3530MX results for performance and battery life. It would still lose to Sandy Bridge quite soundly on many tests, I'm sure, but it's still a significant difference in clock speed over the A8-3500M..
  • Jasker - Tuesday, June 14, 2011 - link

    One thing that is really interesting that isn't brought up here is the amount of power used during gaming. Not only do you get much better gaming than Intel, but you also get much less power. Double whammy.

Log in

Don't have an account? Sign up now