Battery Life: Minor and Major Improvements

As mentioned earlier, ASUS finally moved to something slightly higher capacity than the 48Wh batteries we’ve seen in so many entry-level notebooks. The result is better battery life, but compared to Arrandale it’s not a huge change in two of our tests. The third test is H.264 playback, and that shows a large increase in battery life. We’ve got the same laptops that we used in our application tests for these charts, but if you want more comparison points we suggest checking out Mobile Bench, where we have results for every laptop we’ve tested in the past year. For example, here’s how the K53E stacks up to one of the few Arrandale-only laptops we’ve tested, the Dell Latitude E6410.

Battery Life - Idle

Battery Life - Internet

Battery Life - H.264 Playback

Relative Battery Life

The ASUS K53E places near the top of our battery life charts, with over seven hours of idle battery life, six hours of Internet surfing, and almost 4.5 hours of H.264 video playback. There’s still a sizeable gap between the K53E and laptops like the U41JF, but that’s more a case of battery capacity than efficiency. With a similar size battery capacity (and a much smaller LCD), HP’s dm1z does last over an hour more in the idle and Internet tests. H.264 content is a place where Sandy Bridge excels, however, and with only a 10 minute difference between the 11.6”-screen HP dm1z and the 15.6”-screen ASUS K53E it’s pretty clear that’s one metric where SNB is more efficient. Looking at relative battery life (i.e. true power efficiency), the K53E is only bested by Brazos (and Atom and CULV) in the Internet test. Even the U41JF can’t match the K53E for efficiency, despite underclocking the i3-380M to 700-900MHz (instead of the normal 933-1200MHz) and having a smaller 14” LCD.

For other battery life tests, the K53E lasted just 73 to 83 minutes in simulated gaming (looping 3DMark06/03, respectively), so at heavy loads SNB clearly isn’t a panacea. Setting the LCD to 100% brightness (instead of 50%, which corresponds with 100nits), idle battery life drops 10%. Put another way, the LCD uses an extra 0.87W at 205nits. That’s a very low figure for a 15.6” LCD, but then the maximum brightness isn’t very impressive and as we’ll see shortly, the LCD is otherwise a complete disappointment. Calculated power draw at idle running on battery power is just 7.91W, which used to be Atom territory (though the ASUS Eee PC 1001P drops that figure to just 4.4W). Internet surfing bumps the average power use to 9.33W, which is still extremely good, and H.264 playback requires 12.58W. We’re basically looking at 6-15 times the performance of Atom (Pineview), all while requiring just 40-80% more power at low loads. Connecting the AC adapter, we saw slightly higher power draw at the outlet, but mostly that comes from the AC adapter efficiency.

There are a couple final points before we leave power and battery life discussions. First, all of this testing was done with a stock Windows 7 installation, so we didn’t use ASUS’ Power4Gear utility to further optimize power requirements (e.g. by shutting off the DVDRW on battery power). In the past, that has usually added at least a few percent to the battery life, which is one of the reasons ASUS’ current laptops often beat their competitors.

The other interesting piece of information is that with Core 2 and Core 2010, we always achieved maximum battery life by setting the CPU to run at 0% minimum and 0% maximum in the advanced power settings (as opposed to 0% min/100% max). With Sandy Bridge, idle battery life still benefits slightly, but it’s within the margin of error (425 vs. 429 minutes); H.264 playback is also within the margin of error (261 vs. 267 minutes), but this time setting the CPU to 0% min/100% max results in the higher battery life. The real kicker is the Internet test: set to 0/0%, the K53E lasted 311 minutes compared to 360 minutes at 0/100%. In other words, with Sandy Bridge it looks like the “hurry up and go to sleep” principle is finally working as intended. This is a pattern we’ve noticed on other SNB laptops, so you can now get the benefits of faster instantaneous performance and better efficiency, at least when you’re running light loads.

Sandy Bridge Gaming Performance, One More Time LCD, Temperatures, and Noise Levels


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  • JarredWalton - Friday, April 08, 2011 - link

    Our battery life testing has always targeted maximum battery life while still being able to complete all tasks. So with Core 2 Duo, Athlon II, Core i-series, etc. we've always set minimum CPU and maximum CPU to 0%, and enabled any special power saving features as applicable. (I should note that there are exceptions to the above: Atom, Brazos, and CULV/ULV have always been tested at 0/100% CPU settings, mostly because they are already slow--particularly Atom. The laptop needs to be able to play our H.264 video without stuttering or dropping frames.) On the ASUS U41JF, if you use the "Battery Saving" Power4Gear profile, it automatically underclocks and locks the CPU to run at no more than 900MHz. Running stock instead of underclocked reduces battery life by 5-10% as noted in the U41JF review. Finally, as I point out, it's interesting that for SNB, 0/0% actually reduces battery life compared to 0/100% CPU in two of the three battery tests--this is not the case with Arrandale.

    Regarding power efficiency: 10 to 15% better efficiency is "similar" in my book. The 30% difference in H.264 is a lot more pronounced, true. As for SSD vs. HDD, SSDs really don't use that much less power at idle, and often even under load. Look at the ASUS U30Jc with an SSD comparison: SSD wins by 7% at idle, HDD wins by 3% in the Internet, and the H.264 is a tie (0.3% difference). The 17.3" LCD vs. 15.6" LCD is going to be more than a 5% difference I'd bet, and the K53E actually has an LCD that appears to use very little power. The same applies to the comparison with Dell's E6410: 15-20% isn't massive in my book, but 55% certainly qualifies. It's better, yes, but not a huge change.

    Your E-350 comment is already addressed in the text if you don't take just one piece of the paragraph: "Ah, but the E-350 has a much better IGP, right? Well, maybe it’s better, but it’s certainly not faster than Intel’s HD 3000 when it’s bottlenecked by the CPU...." I suppose I can add "and memory bandwidth" for you though.

    Anyway, what individuals think of DC vs. QC Sandy Bridge is a matter of opinion. I was more impressed by QC, and if I could get QC over DC in the form factor I want that's what I'd do. Dell's XPS L502x for instance gives you both options, and with a moderately large 15.6" chassis the quad-core is an easy sell for me. Others might be more impressed with the dual-core stuff, but we've had dual-core Arrandale for a year and increasing battery life by 20% with 15-20% more performance is still "incremental" in my book.
  • Shadowmaster625 - Friday, April 08, 2011 - link

    "What about AMD’s Fusion E-350 platform? If the 3DMark results hold in our actual gaming tests, Intel’s “horrible” HD 3000 IGP offers over twice the performance of the HD 6310M. In fact, even an Arrandale IGP would come within 10% of the E-350 results in 3DMark. It’s not that we love Intel or want them to pummel AMD, and we understand that the E-350 competes in a lower price bracket. Still, many people like to get carried away in discussions of how much better AMD’s graphics are compared to Intel’s IGP. That’s certainly true when you’re looking at discrete GPUs, and compatibility is still better with AMD and NVIDIA drivers, but the latest SNB IGP changed the status quo."

    What is this nonsense? You claim to understand that the E-350 competes in a lower price bracket. But it is obvious you simply cannot comprehend that there is a difference between a $50 part and a $225 part. Sandy Bridge is too expensive to ever change the status quo. That product line is so expensive that it changes nothing. Except you are paying the price of a discrete gpu, plus a hefty markup, to have an integrated gpu. Intel will not lower those prices even when llano blows it out of the sky for half the price.
  • JarredWalton - Friday, April 08, 2011 - link

    Did you even read the whole conclusion? Where I repeatedly cede the sub-$600 territory to AMD? And I only mention Llano nine times throughout the review. Obviously nonsense.... Except, $600 SNB is now a viable alternative to what used to be $900 laptops. The U30Jc is slower in every regard than the current i5-2xxx CPUs -- the 310M can't keep up with HD 3000, and Arrandale can't keep up with SNB. So yes, that's "changing the status quo". Integrated graphics no longer suck quite as bad, to the point where HD 5470 is dead and so is G 310M. Reply
  • JPForums - Friday, April 08, 2011 - link

    H.264 content is a place where Sandy Bridge excels, however, and with only a 10 minute difference between the 11.6”-screen HP dm1z and the 15.6”-screen ASUS K53E it’s pretty clear that’s one metric where SNB is more efficient.

    SNB is probably more efficient at H.264 decode, but one fact makes it a little less than clear. Ironically, you point it out here:

    Setting the LCD to 100% brightness (instead of 50%, which corresponds with 100nits), idle battery life drops 10%. Put another way, the LCD uses an extra 0.87W at 205nits. That’s a very low figure for a 15.6” LCD, ...

    That does seem like a rather low power draw for a 15.6" and makes me wonder how much power HP's 11.6" draws. The question is purely academic, though, as I would be willing to sacrifice some battery life for a better looking screen. Further, 13.3" is about as small as I'll go.

    That aside, this article makes me wonder how well similarly equipped notebooks with Optimus technology will do. It would be nice to see some designs that get most of the battery life under normal usage while giving you the ability to game when you want. Hopefully, nVidia realizes that the GPU is no longer needed for H.264 decode with SNB and will leave the CPU to take care of it.
  • JarredWalton - Friday, April 08, 2011 - link

    All of the Optimus Arrandale stuff I tested used the IGP, because it was sufficient for H.264 decode. However, oddly enough the Optimus laptops never quite seem to get to the same battery life levels as the IGP-only systems. Okay, I only tested one of the latter (Dell Latitude E6410), but for a 14" chassis the relative battery life was much better than any other Arrandale laptop we tested.

    Perhaps the real culprit is the batteries: they all come with Wh ratings, but I can tell you from personal experience that some 2500mAh NiMH Energizer AA rechargeables have got nothing on 2000mAh NiMH Eneloop AA rechargeables. But unfortunately, I don't know of a good way to independently rate a laptop battery to say exactly how good it is--not without some sophisticated equipment (and tearing the batteries apart, which would likely be frowned on). So I "hope" that these Lithium Ion batteries are more consistent than NiMH, even if they're not.
  • strikeback03 - Monday, April 11, 2011 - link

    I have some 2500 mAh Energizer AA batteries that I bought 4-5 years ago that are absolute trash. Even when new they self-discharged so fast that their apparent capacity was much lower than the rating. Fully charge them using an intelligent charger then leave them in a drawer for a few weeks and they would be dead. Nevermind low-discharge batteries like the Eneloop, even compared to other standard NiMH batteries they are awful.

    As far as Li-Ion batteries go it is relatively easy to test in a way that makes them look really good (third-party camera/phone batteries are infamous for this). I would hope that laptop batteries from well-known brands wouldn't follow the same pattern, but I suppose you never know.
  • JarredWalton - Monday, April 11, 2011 - link

    I've noticed over the years that some laptop batteries will self-discharge at a faster rate than others. I've never really tried to determine how fast that rate is, but it would be interesting to fully charge every laptop battery I have, wait three weeks (with them unplugged), then check how much charge is remaining. Most laptop batteries seem to lose most of their charge within about three months, so they definitely wouldn't keep up with the Eneloop stuff. Reply
  • krumme - Friday, April 08, 2011 - link

    An e350 is 74mm2 - the same as Atom - this is exact numbers.
    The e350 is aprox 40usd (63usd list price - exact number) exactly the same as Atom d550 sans ion
    The e350 have fewer pins -> cheaper to integrate for the OEM than Atom

    How difficult is it to compare in the same segments?

    As an owner of an Intel sb e2520m machine (dell e6420) and an Atom nettop, i can safely say this Article is the most lousy and biased article for years.

    This leads to the most stupid buying decisions all over. Do you seriously think the e350 is a SB competitor?

    What a shame
  • JarredWalton - Friday, April 08, 2011 - link

    You're simply not getting it: less than twice the cost, more than double (actually, quadruple CPU and double GPU) the performance. That's my point. If you want an inexpensive netbook, Brazos wins. If you want an all-around laptop, E-350 is better than Atom, but Atom was horrible. What exactly is stupid about telling people that Brazos isn't the greatest thing since sliced bread? It fills a niche, but for me Brazos is at best a secondary laptop.

    Or to rephrase: do you seriously think everyone should buy Brazos and forget about better options that cost more? What a shame.
  • krumme - Friday, April 08, 2011 - link

    Who would have imagined the brazos came to 15.6" right off?

    Probably it will be all over even in desktops within the next year, when TSMC 40nm capacity expands big time.

    The OEM knows their market so the consumers clearly have a different view of performance than you and I do.

    Even with a ssd i cant tell the difference selecting max 50% perf., doing all the normal office stuff and hd video. The brazos is paired with normal hd, and its aparently just fast enough not to be noticed for the target group. And battery life is just okey. The target group would probably prefer more battery life if they could select themselves - if lower price was not possible.

    I think a review and the conclusions - with its interpretation of facts - should reflect the needs and the perspective of the target group.

    Sandy bridge is an excellent CPU with even better power management, but its like comparing a gtx570 to an 330m if you compare it to brazos. It doesnt make sense. Its different different segments, different purpose.

    If some less informed buyers - lets say the ones that buy cheap stuff - reads this article they might get the impression the HP brazos is very slow, and will select an Intel brand instead. And it will be Atom something not an i3/i5 or Llano - whatever - for that matter. And Brazos is the best since sliced bread compared to an Atom.

    Normal users dont use time installing programs or games, encode, whatever. And when they do they take a cup of coffee.

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