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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medi01 - Thursday, December 15, 2011 - link
It's not about "what is Prime's color gamut", but rather "how does it compare to other tablets".Hopefully it will become standard part of your tests, since brightness/contrast tell only small part of the story.
Ric_Margiotta - Thursday, December 15, 2011 - link
Thanks for this follow-up article, Anand! It was a good read and answered some of my remaining questions about the TF Prime. Still looking forward to picking one of these up in January!sotoa - Thursday, December 15, 2011 - link
Too bad these weren't ready in bulk for Christmas. Not to mention ICS.tipoo - Thursday, December 15, 2011 - link
I read elsewhere that engineering samples of Tegra 3 weren't performing as much better as Nvidia originally expected them to, due to the cores and GPU being constrained for memory bandwidth. I don't know of them changing this in the original design. I'm curious how much ICS will improve T3 performance with its better multithreading and better GPU acceleration, and how much comes down to all the elements competing for bandwidth or some other hardware limitation?druter - Thursday, December 15, 2011 - link
I guess we should not have expected a non apple slanted review from such a mac fanboy site. I dispair for tech journalism when the point becomes less about an honest unbiased review and more about ones allegiance to apple.Nice try though to sound unbiased though, stating that it is a much improved tablet, your apple bias showed through though when you indicated you felt that it was only in comparison to other Androids and that it was still below anything Mac.
The lesson I learned don't come to Anandtech.com when you want an honest unbiased review.
piiman - Thursday, December 15, 2011 - link
If you think this is an Apple fan site why do you even come here? Just so you can bash the reviews?tipoo - Thursday, December 15, 2011 - link
What parts of this came across as biased? To me it seemed all the facts were laid out impartially, and they put effort into correcting the old battery life measurements as well as promised performance updates when ICS hits. If everything comes back to the iPad, its for a reason, like it or not its still the standards bearer for these tablets, and I'm a hardcore Android user. I think the Prime will be better than the iPad personally when ICS hits, but the review is based on current software of course.IKeelU - Thursday, December 15, 2011 - link
It's important to show how it performs against the iPad, especially with regards to battery life. Most people don't care about android vs iOS, they just want a media consumption device, and will therefore choose the device that allows them to do that better.Second, the numbers for battery life are in Apple's favor. It would be biased to ignore them.
Sounds to me like you would be better served by going to an Android fanboy website.
Belard - Thursday, December 15, 2011 - link
You are a fool druter. I and others do not know WHAT you think you read or watched.A) Anand isn't much of a tablet user (AFAIK from his previous articles)
B) He uses all kinds of technology - he does have the right to use what he wants for his personal uses, no? He uses AMD and intel for his own servers and in general - has kept standards pretty good on this sight.
C) All devices WILL compare market leaders, including the iPad. With what is on the market TODAY from Samsung, ASUS, Toshiba, etc - None of them have the battery or GPU (graphics) performance of the 9 month old iPad2 and some are below that of an iPad1 especially when it comes to battery life.
D) "below anything mac"?? he didn't compare the TF-Prime to any Mac. Apple only has one type of tablet on the market and its NOT a Macintosh. He stated the simple fact that tablets DO NOT replace actual notebooks. That is true if the iPad2 as well.
E) Use the best tool for the job or personal preference and budget. Simple as that, eh? I build my own desktops, own ThinkPad notebooks and have an iPad. My dislike for apple is the same for Microsoft, so it just doesn't matter.
F) Get over yourself.
melgross - Thursday, December 15, 2011 - link
Some people aren't happy unless something is reviewed as being much better than any comparable Apple product.Like it or not, the iPad is still the gold standard, and everything is going to be compared to that. This guy will be very unhappy in March when the new one comes out.