Battery Life

With 39 hours to test I was pretty limited in what I could do when it came to battery life testing. I was able to run through two tests (one run a piece) and only in one configuration each. I wanted to see how Tegra 3 and the Prime fared in the worst case scenario so I picked the Normal power profile. Over the coming days I'll look at battery life in the other two profiles as well, not to mention run through more iterations of our test suite.

My bigger concern has to do with the malfunctioning WiFi in my review unit. For our video playback battery life test WiFi was on but not actively being used, those numbers should be ok. It's our general use test that loads web pages and downloads emails over WiFi and it's there that I believe things could've suffered a bit.

In both cases I saw around 9 hours of continuous battery life out of the Transformer Prime, without its dock. These numbers are a bit lower than the original Transformer but it's unclear to me how much of this is due to the additional cores/frequency or the misbehaving WiFi. The fact that we're within striking range of the original Transformer with the Prime running in Normal mode tells me that it's possible to actually exceed the Transformer's battery life with the Balanced or Power Saver profiles. That's very impressive for an SoC built on the same manufacturing process as its predecessor but with twice the CPU cores and a beefier GPU.

Video Playback - H.264 720p Base Profile (No B-Frames)

General Usage - Web Browsing, Email & Music Playback

What I'm not seeing however is the impressive gains in battery life NVIDIA promised its companion core would deliver. I'm not saying that the companion core doesn't deliver a tangible improvement in battery life, I'm just saying that I need more time to know for sure.

That the Transformer Prime can deliver roughly the same battery life as its predecessor without any power profile tweaking may be good enough for many users. Both ASUS and NVIDIA shared their own numbers which peg the Prime's battery life in the 10 - 13 hour range. As I mentioned before, I'll have more data in the coming days.

Update - With a replacement Transformer Prime in house, battery life is looking a lot better already:

Update 2: Even more battery life results in our follow-up

Camera Quality The Dock & Keyboard
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  • Penti - Thursday, December 1, 2011 - link

    It looks like they have finally a pretty good product and software, they should dump the Eee pad and the redundant awkward name now and it would be even better :)

    Would love to see better optimized software, but this is what you could have expected plus with a great screen and I wonder how well it would work as a thin-client with Citrix? Keyboard and touchpad should make it a pretty good experience, does it? Chromebooks can just forget it any way :) Here we have form factor, local software, multimedia (Chromebooks are not even having accelerated H.264 as standard) and so on. With keyboard docked and standard, and not just a browser that was obvious would be replaced by a Android distribution of some kind any way. Maybe that time is now. Even though I wouldn't except Asus to complete that process. Fun to see them kinda getting there act together though.
  • Malih - Thursday, December 1, 2011 - link

    I agree that Eee is an awful name, especially for a flagship/cutting-edge product.
    Eee is associated with low-end Atom netbooks, since that's the first device that uses the name. And I always hate that Samsung name their mobile devices Galaxy.

    IMHO, the name Zenbook sounds good, maybe they should invent something consistent with that for their top-line tablet, Zenpad?
  • Penti - Friday, December 2, 2011 - link

    Zenbook is still kinda awkward but it's better, ZenPad doesn't do anything for me and sounds silly. Transformer Prime is a pretty good name. Transformer might cause some confusion though, if they decide to release one without any keyboard attachment. Their Windows tablet PCs (slates as of now) might as well get some updated finish and release as a Zenbook slate though.
  • MamiyaOtaru - Thursday, December 1, 2011 - link

    "The 16:9 panel measures 10.1-inches diagonally, giving it a larger surface area than the iPad 2's 9.7-inch 4:3 display. "

    If you do your math, this isn't actually true. A 10.1" 16:9 display has a surface area of 43.58", while a 9.7" 4:3 display has a surface area of 45.17". This is one of the main reasons behind widescreen, they get to trumpet a larger diagonal measurement while actually saving costs on smaller total area. I am a little disappointed you fell for it.
  • MamiyaOtaru - Thursday, December 1, 2011 - link

    some numbers you can plug in for verification (rounding all around!):
    16:9 10.0" display has sides of 8.8 and 4.951. 8.8/4.95 ~= 16/9 (correct ratios). 8.8² + 4.95² ~= 10.1² (correct dimensions for given diagonal, shown via pythagorean theorem).
    area then: 8.8*4.95 = 43.96.

    4:3 9.7" display has sides of 7.76 and 5.82. 7.76/5.82 ~= 4/3 (correct ratios). 7.76²+5.81² ~= 9.7² (correct dimensions for given diagonal, shown via pythagorean theorem).
    area: 7.76*5.81=45.09.

    45.09 is larger than 43.96. Ipad2 has a screen with a larger surface area. Run the numbers. Do it without dropping as many places as I did in this post, result will be the same. Again, disappointing

    (I don't have a horse in this race, I own no Apple products. I do hate widescreen monitors though)
  • MamiyaOtaru - Thursday, December 1, 2011 - link

    interestingly, the gap was closed somewhat when I dropped more places in typing up the second post. The first is more accurate, and the gap is bigger. But they both show the ipad as having more surface area, and that will hold true with pretty much whatever level of exactitude one wishes to calculate it
  • Anand Lal Shimpi - Thursday, December 1, 2011 - link

    It's actually a 16:10 panel, my statement was incorrect. But the Prime's display measures roughly 8.5" x 5.25". The iPad 2 by comparison measures approximately 7.75" x 5.75". 44.625 in^2 vs. 44.5625 in^2, giving the Prime a slightly larger display (albeit negligible).
  • Solandri - Thursday, December 1, 2011 - link

    At 9.7" diagonal and 4:3 aspect ratio, the iPad 2's screen is 7.76" x 5.82".

    At a 10.1" diagonal and 16:10 aspect ratio, the Prime's display is 8.56" x 5.35".
  • Solandri - Thursday, December 1, 2011 - link

    Anand's math is right. His aspect ratio is wrong. The Transformer Prime has a 1280x800 screen, which is 16:10, not 16:9. At a 16:10 aspect ratio, you end up with 45.85 square inches of surface area.

    Personally I think 16:10 is the "right" aspect ratio for a multifunction device. You waste10% of the screen when displaying a 16:9 video. A 4:3 device wastes 25% of the screen. The extra width is nicer for web browsing too.

    Where the 4:3 screen does better is displaying pages scanned from paper or magazines. Subtracting a 1-inch margin along all four sides, a 4:3 screen wastes 4% of its screen displaying a Letter-sized sheet of paper, while a 16:10 wastes 13%. (With A4 paper and 2-cm margins, it's reversed. The 4:3 wastes 12%, the 16:10 screen wastes 6%.)

    But that's counter to the whole point of tablets - to free us from the shackles of a paper-bound world. As a media consumption device, I think 16:10 is the better aspect ratio. It's almost exactly the golden ratio too (1.62), so most art which is produced will fit in it better.
  • GnillGnoll - Friday, December 2, 2011 - link

    For browsing the web and reading, portrait orientation is often a better fit. Though it requires a certain minimum width and resolution to work really well.

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