ASUS Eee Pad Transformer Prime Review Part II: Battery Life & More
by Anand Lal Shimpi on December 15, 2011 3:45 AM ESTChanges to the Browser & Performance Analysis
Honeycomb's web browser has always had an issue properly loading Reddit.com. In testing the Transformer Prime, the fact that Reddit loaded properly was one of the first things I noticed—leading me to believe that ASUS and NVIDIA had done some work to customize the browser for the Prime and Tegra 3. This customization work is also evident if you watch the manner in which web pages are loaded on the Prime versus any other Honeycomb tablet, including the original Eee Pad Transformer. The difference isn't really better or worse, just clearly different.
It turns out that there are a number of improvements to the Honeycomb browser for Tegra 3 platforms. The first has to do with threading and GPU acceleration. Google has been steadily moving away from using its skia libraries for drawing to the screen in Android. These libraries are mostly run on the CPU. With Honeycomb Google moved many elements of the OS to OpenGL ES based rendering, but parts of the browser still use these non-GPU accelerated skia libraries for displaying rendered web pages. With Ice Cream Sandwich (Android 4.x), Google moved the browser to OpenGL rendering but unfortunately Tegra 3 would debut on Honeycomb and not ICS so something had to be done. NVIDIA made two primary changes to the Honeycomb browser for Tegra 3. For starters, it further threaded a lot of the skia libraries to better take advantage of the four A9 cores in T3. It also moved some more components of the browser's display pipeline to OpenGL. The change isn't nearly as dramatic as what we'll see with the move to ICS, but it's a step forward.
There are some slight improvements in scrolling performance compared to the Tegra 2 build of Honeycomb. You don't get as much white blocking while scrolling on the TF Prime compared to the original (only when scrolling naturally, using the fast scroll bar on the right is the same on both).
NVIDIA also updated the JavaScript rendering engine in the Tegra 3 build of Honeycomb, which is likely responsible for some of the gains we saw in our original SunSpider numbers (higher CPU clocks helps a bit here as well).
The impact on web page loading performance isn't as dramatic as you'd expect. In general the Prime loads web pages in about the same amount of time as the original Transformer. Some web pages load quicker others load slower and it really varies from run to run. In my testing the original Transformer actually seemed to be more consistent in web page loading times. Whatever changes NVIDIA made to the browser seems to have resulted in this behavior. While there's no major performance gain when it comes to loading most web pages, the difference is that parts of the workload are spread across more cores, allowing each of the cores to run at a lower frequency and thus voltage.
I stand by my original assessment of the Prime's performance. The place you notice the additional CPU cores the most is when multitasking; unfortunately Honeycomb still degrades into a sluggish mess if you ask too much of it, which in turn limits the seat of the pants impact from having twice as many cores. Whereas the move from one to two cores was instantly noticeable on Android phones, the move from two to four is understandably less appreciable. The Prime as a whole feels much faster than its predecessor, but it's unclear to me how much of that is due to the faster GPU, higher CPU clocks, increase in memory bandwidth, NEON support, or the additional cores. I'm willing to bet that the faster GPU and increase in CPU clocks are the most noticeable of the improvements, followed by the increase in core count. I don't mind the extra cores, but I do get the feeling that we'd be better off with two faster cores than four A9s. With A15 and Krait really designed for 28nm, NVIDIA's decision to increase core count at 40nm was probably better for end users than simply increasing CPU clocks on Tegra 2.
I suspect Ice Cream Sandwich will remove some of the software bottlenecks that make the Prime feel sluggish under heavy load, at which point I may have to revisit this assessment. There's also the concern of how Tegra 3 will stack up against Krait based solutions in a few months time. I still feel like the Transformer Prime is a good buy today if you're looking for an Android tablet, but 28nm silicon is less than six months away....
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kenyee - Thursday, December 15, 2011 - link
I'm not sure this would show up in the color gamut tests because the original Transformer had an 18-bit dithered screen...lordmetroid - Thursday, December 15, 2011 - link
Can I install whatever operating system I want?jllcmu04@hotmail.com - Thursday, December 15, 2011 - link
Hi,First off, I am very happy for your thoroughness. You always try your best in your reviews. My trouble is with your CONSTANT comparison to mac book air. How expensive is your mac book air, and what processor and hd etc come with it? Even if you take the 64 GB model TF-Prime, you are still easily a couple hundred under MBA. Also, as you mentioned, one is a tablet + dock , while the other is designed, albeit very very well, as a laptop. Now the comparison to netbooks is one I can understand, but the constant comparison to MBA I feel degrades from true evaluation. One thing I found funny, is that even with the comparison to a system that is much more expensive, it still is able to keep up some.
Anyway, thanks for a great review!
J
Graag - Thursday, December 15, 2011 - link
"Now the comparison to netbooks is one I can understand, but the constant comparison to MBA I feel degrades from true evaluation."I think that comparisons like this are actually very helpful, since there are a decent number of people who want to know whether they need a MBA/Ultrabook, or whether they can save $400-$500 and use a tablet. And, particularly because tablets are still pretty new (as mainstream devices, anyway), it's also useful to delineate the boundaries between laptops and tablets.
"One thing I found funny, is that even with the comparison to a system that is much more expensive, it still is able to keep up some."
This is a very important point for some users - and a point that wouldn't have been made but for comparing the tablet to a MBA.
DanNeely - Thursday, December 15, 2011 - link
There's not a major ultraportable laptop platform between netbooks and the mba. Some of the cheaper ultrabooks might drop into it but none are there in meaningful volumes yet.justaviking - Thursday, December 15, 2011 - link
I cannot get your video to load."An error has occured, please try again later."
vision33r - Thursday, December 15, 2011 - link
1.4GHZ Tegra 3 is barely faster than the iPad 2 and we know that thing only runs at 1GHZ.By March, we know the A6 will be quad-core and most likely run at 1.2GHZ and Apple always make a huge performance leap just to keep the device potent enough for a whole year.
Why would anyone want to buy the TF Prime that will be the fastest Android tab for about 3 month for $500
Samsung will have their own quad-core Exynos out soon too.
iPad 3 will also have a 200ppi display which will make every other tablet look like a pixel board.
This is not an Apple fan post, just stating the what the competition will be and Tegra 3 is a very small upgrade.
eddman - Thursday, December 15, 2011 - link
No, It should read "transformer prime is barely faster than the iPad 2".There is no way tegra 3 is slower than A5, it's the software. While ios is fully optimized for A5, honeycomb can't even utilize dual-core chips properly. Let's see what ICS would do.
Personally, I'm waiting for windows 8 tablets.
shady28 - Friday, December 23, 2011 - link
A lot of semantics there. True that A5 is probably slower than Tegra 3, but also from the article there is no significant performance difference between an iPad 2 vs Transformer Prime. The OS and platform do count.
I'm a bit disappointed too though. I really thought the quad core Tegra 3 would be at least 40% or so faster than similar clocked A9 based systems just because of the extra 2 processors, but apparently not. I'm thinking maybe Android isn't quite optimized for more than 2 cores yet.
IntelUser2000 - Thursday, December 15, 2011 - link
"Whereas the move from one to two cores was instantly noticeable on Android phones, the move from two to four is understandably less appreciable."It looks like 4 core is for the forseeable future a practical limit for the "multi-core" era before we opt for another approach.
The gains in battery life in web browsing and video playback is likely not due to having extra cores and being able to clock them down faster, but the more advanced power saving available in Tegra 3.
They noted something similar to Intel's DPST(Display Power Saving Technology), along with better C states compared to Tegra 2.