Battery Life

I didn’t get my hands on the Haswell S7 until a few hours after I landed in Taipei. My hotel’s in-room internet was throttled to around 2.5Mbps, which wasn’t enough bandwidth to reliably run our web browsing battery life tests. Luckily, I had my review copy of PCMark 8 on hand with its new built in battery life tests. I asked Jarred to run comparison data on the Ivy Bridge S7.

We had time to perform multiple runs on two of the tests: Home and Creative.

From the PCMark 8 Technical Guide:

The PCMark 8 Home benchmark test includes a set of workloads that reflect common tasks and activities performed by a typical person at home. These workloads generally have low computational requirements making the PCMark 8 Home benchmark suitable for testing the performance of low-cost tablets, notebooks and desktops.

The PCMark 8 Home benchmark test contains the following workloads: Web Browsing, Writing, Casual Gaming, Photo Editing and Video Chat.

The PCMark 8 Creative benchmark test includes a set of workloads that reflect tasks and activities typical of more advanced home computer users. With more demanding requirements than the Home benchmark, the PCMark 8 Creative test is suitable for testing the performance of mid-range computer systems. Your system must have a GPU with full DirectX 11 support in order to run all the workloads in the PCMark 8 Creative benchmark.

The PCMark 8 Creative benchmark test contains the following workloads: Web Browsing, Photo Editing, Batch Photo Editing, Video Editing, Media to Go, Mainstream Gaming and Group Video Chat.

As always, I calibrated both displays to the same brightness (200 nits). In the case of the Haswell based S7, I disabled all additional display power saving options in the Intel driver. Keeping in mind the new S7 has a 33% larger battery, I’m presenting both absolute battery life numbers as well as minutes per Wh for normalized comparisons.

The PCMark 8 Home battery life test is the lighter of the two, and thus has the best chance of showing peak improvement on Haswell. The results are very good:

PCMark 8 Battery Life
  PCMark 8 Home PCMark 8 Home (Normalized) PCMark 8 Creative PCMark 8 Creative (Normalized)
Acer Aspire S7-391 (Core i7-3517U) 2.83 hours 4.857 mins/Wh 3.35 hours 5.743 mins/Wh
Acer Aspire S7-392 (Core i7-4500U) 5.2 hours 6.783 mins/Wh 5.12 hours 6.674 mins/Wh
Haswell Advantage   39.6%   16.2%

In both benchmarks, Haswell ULT delivers 11 - 14% better performance and substantially longer battery life. Normalized for battery capacity, Haswell ULT offers 16% better battery life in the Creative test and almost 40% better battery life in the Home test. Note that the performance advantage pretty much disappears once we move to the Balanced power profile with the laptop connected to the wall.

PCMark 8 Performance
  PCMark 8 Home (Power Saver) PCMark 8 Home (Balanced) PCMark 8 Creative (Power Saver) PCMark 8 Creative (Balanced)
Acer Aspire S7-391 (Core i7-3517U) 1595 2694 1391 2508
Acer Aspire S7-392 (Core i7-4500U) 1777 2832 1583 2553
Haswell Advantage 11.4% 5.1% 13.8% 1.8%

Update: I made it back to the US, equipped with decent internet speeds, I was able to run our light 2013 web browsing battery life test. The increase in battery life is tremendous:

Battery Life 2013 - Light

The new S7 delivers over 2x the battery life of the old model. Normalizing for battery capacity, the improvement due to Haswell is 57.5%. These results track perfectly with what we saw in PCMark 8. Workloads with greater idle time will show the biggest improvement in battery life thanks to Haswell ULT.

 

The Test System and Haswell ULT SKUs CPU Performance
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  • StealthGhost - Sunday, June 09, 2013 - link

    Is PCMark 8 Home less demanding than 1080p video? If not, it doesn't seem like the Asus can call itself an Ultrabook.

    Still, impressive gains in battery life. I hope this will carry over, to some extent at least, into the CPUs that will be in laptops like the MacBook Pros. Guess we will have to see when that review comes out =)
    Reply
  • StealthGhost - Sunday, June 09, 2013 - link

    *Acer Reply
  • Death666Angel - Sunday, June 09, 2013 - link

    As far as I know the Ultrabook specs don't define a minimum luminance for the display. So Anand's test isn't relevant for the Ultrabook spec. Reply
  • axien86 - Sunday, June 09, 2013 - link

    Laptopmag just reviewed the Sony Vaio based on the i7-4500u and they also noted that performance wise the Haswell offered marginal improvement over Ivy Bridge laptops, while battery life was indicated as improved.

    One important characteristic that most laptop users want to know is regards to heat and fan noise. Laptopmag found that the Haswell i7-4500u based Sony Vaio found that the back of the laptop "reached a more troubling 110 degrees." They also found fan noise was definitely noticeable in a quiet room just running Word and a Youtube video.

    http://www.laptopmag.com/reviews/laptops/sony-vaio...

    The question is, why hasn't Anandtech run extensive temperature and noise characteristic analysis on Intel Haswell processors and your current laptop?
    Reply
  • Kristian Vättö - Sunday, June 09, 2013 - link

    Likely because of lack of time. As Anand said in the article, he got the unit while in Computex, so basically he did the review between meetings. I'm pretty sure he didn't have the equipment with him to do temperature or noise tests properly but I'm sure this is something that will be tested in later reviews.

    Also, keep in mind that heat and fan noise are system-dependent. If the Vaio has poor cooling, then it will be hot and loud but that's not Haswell's fault (I'm not saying this is the case but we obviously need more reviews before any conclusions can be drawn).
    Reply
  • mavere - Sunday, June 09, 2013 - link

    "The question is, why hasn't Anandtech run extensive temperature and noise characteristic analysis on Intel Haswell processors and your current laptop?"

    The WHr of battery that a laptop consumes is the exact same thing as its heat output.

    Anand is trying to test the Haswell platform, not the design deficiencies of any specific manufacturer. Sony's problems are its own.
    Reply
  • n13L5 - Sunday, June 09, 2013 - link

    Cause they had to run their test in Taiwan with a borrowed machine?

    I was rather disturbed by the temperature of Sony's Vaio Pro, as well as the instability of the carbon case, which must be paper thin... And their keyboard backlight has the worst bleed I've ever seen, they should have a look at Lenovo and Samsung keyboards...

    Well, I'll be waiting for more tests and the ULT Haswell with the Iris 5100 GPU. Maybe that'll rack up a high enough temperature to fry a steak.
    Reply
  • akbisw - Monday, June 10, 2013 - link

    Sony has terrible cooling system in their laptops in general. The worst I have seen done by any manufacturer. Even my my old acer before their "reiteration" had better cooling design than current VAIO systems. Reply
  • Dnann - Friday, June 14, 2013 - link

    He probably didn't have the time considering the circumstances... Reply
  • DanNeely - Sunday, June 09, 2013 - link

    The fact that companies historically known for horrible battery life are getting good results out of Haswell with Intel's help is promising; but starting from such a horribly low baseline makes getting gains much easier. I'm much more interested in seeing what companies who've historically offered good battery run times will be able to do with Haswell. Reply

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