ASUS Eee Pad Transformer Prime & NVIDIA Tegra 3 Review
by Anand Lal Shimpi on December 1, 2011 1:00 AM ESTThe Three Power Profiles
There are three power profiles ASUS and NVIDIA have defined on the Prime: Normal, Balanced and Power Saver. Normal allows the CPU to run at up to 1.4GHz with only a single core active, and 1.3GHz otherwise. Balanced is the default setting and it drops maximum CPU clock to 1.2GHz and favors lower clock/voltage targets on the curve compared to Normal mode. Power Saver caps CPU frequency at 1GHz with 1 - 2 cores active, 760MHz with 3 cores active and 620MHz with 4 cores active. It's unclear what the impact is on GPU clocks/performance.
Regardless of power profile, video playback capabilities are untouched - all profiles are able to play 1080p High Profile H.264 content at up to 40Mbps.
The performance impact of these various profiles varies depending on what you're doing. I ran a mixture of CPU and GPU bound tests in all profiles to measure their impact. The results are below:
I reformatted the SunSpider and BrowserMark scores to keep the magnitude of the numbers in line with the rest in the chart, and to make higher numbers = better performance across the board. For the most part you can see that the difference between Normal and Balanced is pretty small. Numerically it works out to be a 5 - 15% gap depending on the benchmark. The latter end of the range is big enough where the performance conscious will want to stay in Normal mode, but it's possible to do without it.
It's interesting to note that the impact on GPU performance isn't that major across the board. It looks like NVIDIA is primarily modulating CPU speed here. The impact on JavaScript rendering performance is huge when you enable the Power Saving mode. In this state the Prime performs like a Tegra 2 based Gingerbread phone.
Power Profiles & Super IPS+ Toggles
Unlike (far too) many of its competitors, ASUS limits its customizations to those that are almost purely functional. ASUS is clearly aware of the fine line between useful improvements and clutter.
The most obvious customization is in the Quick Settings tool:
ASUS' implementation is far busier but it's all extremely useful. You get one tap access to Super IPS+ mode, as well as one tap switching between Power Saving, Balanced and Normal power profiles. I'm pleased to report that toggling any of these modes is pretty much instant, there's hardly any lag between when you tap a button and its impact takes effect. Response time is a particularly important as it directly impacts how frequently the tool is used. In this case I have no issues switching between power profiles because it's pretty much effortless.
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thunng8 - Thursday, December 1, 2011 - link
Not sure about the discrepancies, however, 2.1 is the latest version and it should be the one tested.Also, iOS 5 brought significantly faster openGL drivers, maybe PCWorld were comparing result from a while ago on the ipad2 and iOS4. All onscreen tests are also vsync limited, so the maximum they will ever score is 60fps.
offscreen is somewhat important, as some ipad2 games can render higher output via the HDMI accessory to an external device.
Anand Lal Shimpi - Thursday, December 1, 2011 - link
GLBenchmark 2.1 allows for testing at the same resolution (720p) to enable true apples to apples comparisons of GPUs. There are some slight changes in the workloads as well, so 2.1 numbers aren't directly comparable to 2.0.x numbers.That being said, the iPad 2 should never be slower than the Prime even in an older version of GLBench. I'm not entirely sure what's going on there...
Take care,
Anand
metafor - Friday, December 2, 2011 - link
A new version of PowerVR drivers was released some while back (I believe it came with iOS 5) and improved performance dramatically. That may be the issue.GnillGnoll - Friday, December 2, 2011 - link
46 fps is an old result on iPad 2. With iOS 5 the Egypt Standard test is almost permanently vsync limited at 60 fps (2.0.3 is gone from the online database, but the workload in the Egypt test hasn't changed between that and 2.1)araczynski - Thursday, December 1, 2011 - link
if this is supposed to be the next generation of the android tablets, getting slapped around by the ipad2, WHEN THE IPAD3 is 'just around the corner' makes it almost a joke of an upgrade.i don't have any love for apple (pc guy), but i'll be saving my mountain of pennies for an ipad3, rather than bother with an android tablet, have enough random issues with my free DroidX that i couldn't actually image wanting to pay for the 'experience' in a tablet.
vvk - Thursday, December 1, 2011 - link
If by "around the corner" you meant April or May of the next year than perhaps, based on your needs, you should wait but then if you wait another couple of month you could get the next gen super-duper tablet and so on and so forth. Anyway your life your choice I ain't canceling my preorder based on the Anand's review.gorash - Friday, December 2, 2011 - link
No this is not the next generation of Android, next generation is ICS or Jelly Bean. And iPad 3 is coming next summer.steven75 - Saturday, December 3, 2011 - link
Neither iPad was released in the summer.Ketzal - Thursday, December 1, 2011 - link
I'd like to congratulate on a truly superb review. Given the horribly short time you had to write it and do the testing. You did an amazing job.Your reviews are a true breath of fresh air.
The quality of your reviews make the Engadget and like websites look like total amateurs.
Basically it works like this...if you are pondering a new gadget. Wait for your review. If you say it's the one...it's the one. Buy said gadget.
Live happily ever after.
Congrats, I'll be singing your praises to everyone I know.
Ketzal
Wizzdo - Thursday, December 1, 2011 - link
You should consider getting a low-voltage brain in your next life since Anand does your thinking for you. This way your battery might last as long as the iPad2's.Anand may be good but regardless of his reviews "Happily ever after" is about 6 months in this industry.