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ASUS Eee Pad Transformer Prime review: ASUS Eee Pad Transformer Prime

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The Good The Asus Transformer Prime sports an iPad 2-inspired design that's even thinner and nearly as light, while also managing to include microSD and Micro-HDMI support. The Prime delivers smooth and clear 1080p video, and the 8-megapixel camera captures detail and color more accurately than any other tablet camera we've reviewed. Android 4.0 makes small but significant improvements to Honeycomb.

The Bad Not every game takes advantage of the quad-core CPU, and frame rates can suffer as a result. When connected to the dock keyboard, the tablet is top-heavy and can easily slide off a lap or table if you're not careful.

The Bottom Line The Asus Transformer Prime is the best full-featured Android tablet yet, with a sexy design, thoughtful features, and an impressive camera.

8.0 Overall
  • Design 8
  • Features 8
  • Performance 8

Editors' note: The Asus Transformer Pad TF300 was released in April 2012. Check this blog post for details on the key differences from the Prime.

Also, we changed the Prime's review text to reflect the Android 4.0 update the tablet received in January 2012. Check out this exhaustive interview with Asus detailing -- and putting into perspective -- some of the Prime's technical issues.

Since the launch of the iPad 2, we've been kind of waiting for the Asus Transformer Prime. While we didn't know it existed until a few months ago, the thought of a powerful, robust, and sexy Android tablet has been invading our tablet dreams for months.

Is the Transformer Prime that tablet? With its quad-core Nvidia Tegra 3 processor, it definitely has the potential.

Design
The Prime comes in two colors, amethyst gray (gray and purple) and champagne gold (silver and gold). We got the amethyst gray version for review, and while a purple tablet admittedly wasn't the highest item on our holiday wish list, the gray and purple are blended in a sleek, sexy, and appealing way. Although the aluminum back does a good job of resisting fingerprints, the glossy screen and bezel succumb to them easily.

Asus Eee Pad Transformer Prime Asus Eee Pad Transformer Samsung Galaxy Tab 10.1 Apple iPad 2
Weight in pounds 1.32 1.52 1.24 1.34
Width in inches (landscape) 10.3 10.7 10.1 9.5
Height in inches 7.1 6.9 6.9 7.3
Depth in inches 0.32 0.51 0.34 0.34
Side bezel width in inches (landscape) 0.8 1.1 0.8 0.8

The Prime is about an inch wider than the iPad 2 but a hair thinner; it's also thinner than the Samsung Galaxy Tab 10.1. It's slightly heavier than both aforementioned tablets, but its weight is distributed evenly, so we felt only a negligible difference.


That's the iPad 2 on the left, Transformer Prime in the middle, and Galaxy Tab 10.1 on the right. While they're all really thin, the Prime wins the supermodel contest by a hair.

The Prime takes some design cues from the iPad 2, with a sloped back and rounded corners that don't dig into our palms as the previous Transformer did. For connections, the Prime includes a microSD slot and a Micro-HDMI port on the left side. On the same side are a volume rocker and a microphone pinhole. On the top is a smallish power/lock button, which, though functional, could have protruded more from the chassis so as to feel more tactile. Next to that is a second microphone pinhole and on the right side is a headphone jack. A 40-pin connector port for data/power is located on the bottom.

On the front bezel sits a 1.2-megapixel camera, and almost directly opposite it on the back is an 8-megapixel camera, which is capable of recording 1080p video.

Like the previous Transformer, the Prime connects to an optional keyboard/dock ($150), transforming it (heh) into what is essentially an Android laptop. With the previous Transformer, that connection wasn't the easiest to achieve, but the process has improved dramatically on the Prime, as it now easily slides into the awaiting slot.


With the dock attached, the Prime looks like a typical ultrabook. Well, a purple one at least.

The dock includes a touch pad, a 40-pin data/power connection port on the left, and a full-size SD slot and USB port on the right.

Once connected, the tablet feels a bit top-heavy, though, and could easily slip off a lap or table if enough care isn't taken. Also, the dock is compatible only with the Prime and vice versa. Switching between the older Transformer and this newer one is not supported.

Hardware features
The Prime is the first tablet to house Nvidia's new quad-core processor, the Tegra 3. The Prime also includes 1GB of RAM and comes in either 32GB or 64GB varieties. It has 802.11 b/g/n Wi-Fi support, Bluetooth 2.1+EDR, a gyroscope, and GPS.

The Mobile dock includes an extra battery that--while connected--"feeds" the Prime its power, meaning that the dock's battery will deplete its reserves before the tablet's.

Through its Micro-HDMI port, you can connect the tablet to an HDTV or monitor and play full-screen Android games using both wired Xbox 360 and PS3 game pads, as well as supported wireless game pads through the use of an USB dongle.

Software features
The Prime comes preinstalled with Honeycomb 3.2.1 and is upgradable to Android 4.0 (Ice Cream Sandwich).

Asus MyCloud gives users 8GB of free cloud-based storage space for the lifetime of the Prime (upon registering it) at Asus WebStorage. It also provides remote access to the desktop of a PC or Mac and connects you to the @Vibe online music and radio service.

The File Manager accesses the Prime's root directory, providing easy and organized access to every file on your drive or expanded memory unit. MyNet lets you stream content to DLNA-enabled devices on your network, and with MyLibrary, Asus' e-reader software, you can read and purchase new books directly through the interface.


The File Manager app provides easy access to every file on your tablet.

SuperNote is intended to help with taking notes and allows you to not only type them, but "write" notes with your fingers as well. You can also draw graphs and take pictures or video right from the interface. This could be especially useful for taking notes in a class.

Via Asus' tweaks to the Android interface, you can choose to run the Tegra 3 CPU in normal, balanced, or power-saving modes. While in normal mode, the CPU runs at full speed. In balanced mode and power-saving mode, the CPU speed is throttled to save on battery life. Having this level of control of overall speed is a very welcome feature we hope to see in more tablets.

Asus also adds a Super IPS+ (In-Plane Switching) mode, which boosts the tablet's screen brightness, making reading in sunlight a bit easier. There's also a feature that lets you take screenshots using the Recent Apps button.

Android 4.0 (Ice Cream Sandwich)
Asus recently began sending an over-the-air update for the Transformer Prime that updates it from Honeycomb 3.2.1 to Ice Cream Sandwich (ICS) 4.0.2. ICS is the latest version of Android and so far had only been available on smartphones. This is the first time anyone's seen it on a tablet in the wild, so we're going to dive in and see what, if any, differences there are from Honeycomb.

UI and widgets: The first thing we noticed is that the lock screen now allows you to go straight into the camera app if you want, making the prospect of getting a shot of that supercool thing that's happening right now a bit more likely.

On the home screen, Google has slightly changed the way we access widgets. Honeycomb had a little shortcut at the top of the screen, or you could press and hold the home screen, but now widgets have been grouped with apps.

Tapping the apps shortcut now brings you to a dual apps and widgets section, each with its own tab. Also, swiping through your apps will eventually bring you to widgets. This change is subtle; widgets now feel less hidden and more important than before because of it.

One of the most annoying things about Honeycomb notifications is the way they can pile up, requiring you to close each individual one to get rid of them. Fortunately, ICS lets you kill them all in one fell swoop and let the tablet gods sort it out. Also, instead of simply showing you the last message you've received, ICS consolidates all mail notifications into one, displaying the number of new messages you have.

Settings: With settings you'll notice right off the bat that things are subtly different, with no real huge changes, just a few useful refinements. Options have now been split into four sections: Wireless and networks, Device, Personal, and System. Some features that were crammed in with others in Honeycomb now have their own sections.

The Data usage section details the amount of overall and per-app data you've downloaded over a specific time. Battery now has its own section showing more-detailed power usage information than we're used to on Honeycomb and even tracks battery capacity over a set duration.

Adding a new Google account now gives you options as soon as its created as to which specific Google services you want synced. The Developer options allow you to access things like CPU usage, pointer location, and, my personal favorite, the ability to kill apps as soon as you leave them.

Performance and new features: We didn't notice much difference between ICS and Honeycomb in terms of performance. Previously we experienced no problems with GPS performance and this hasn't changed with the update, although that may have more to do with our office location. Unfortunately, Web browsing is still noticeably slower than on the iPad.

The built-in photo-editing tool is probably the most significant new feature. Options include crop, resize, red-eye, as well plenty of color and tint controls. Additionally, recent apps can now be closed with just a quick side swipe, allowing you to more easily find and kill memory hogs.

ICS feels like a small but significant step up from Honeycomb, and we're looking forward to seeing it on more tablets in the next few months.

Performance
While the Prime's IPS screen was immediately clear and sharp when first we powered it on, it was the screen transitions that really impressed us. The first time we tapped the Apps button, we were treated to a noticeably higher frame rate transition than on any previous Android tablet.

We hoped this fluidity would carry over to apps like Marvel Comics, but that was not the case. Reading a comic through the app on the iPad 2 is still a considerably smoother experience, but this may have something to do with specific optimizations of the iPad app. We can't be sure, however.

The resolution and contrast on the IPS panel are about as impressive as on the previous Transformer or the Asus Slider, but the new Super IPS mode+ increased the brightness up to 570 candelas per square meter (cd/m2), which is the highest brightness we've yet seen on a tablet and makes reading in direct sunlight a bit more tolerable than on other LCD tablets. Still, both the Samsung Galaxy Tab 10.1 and 8.9 are more impressive in terms of displaying vibrant colors.

Tested spec Asus Eee Pad Transformer Prime Sony Tablet S Samsung Galaxy Tab 10.1 Apple iPad 2
Maximum brightness IPS mode (Super IPS) 358 cd/m2 (570 cd/m2) 393 cd/m2 336 cd/m2 432 cd/m2
Default brightness 183 cd/m2 160 cd/m2 336 cd/m2 176 cd/m2
Maximum black level, IPS mode (Super IPS) 0.27 cd/m2 (0.45 cd/m2) 0.47 cd/m2 0.3 cd/m2 0.46 cd/m2
Default black level 0.15 cd/m2 0.19 cd/m2 0.3 cd/m2 0.19 cd/m2
Default contrast ratio 1,220:1 842:1 1,120:1 926:1
Maximum contrast ratio, IPS mode (Super IPS) 1,325:1 (1,266:1) 836:1 1,120:1 939:1

We used Riptide GP as a games performance benchmark. On the Prime, GP runs smoothly with a high frame rate, although maybe a bit lower than on the iPad 2; however, thanks to specific optimizations made by the developer, GP has added graphical effects, like water that splashes on the screen, contributing to the feeling of immersion. Also, on the Prime, the water physics seems to knock you around more violently. Overall, we enjoyed the experience on the Prime much more than on any other platform.


Bladeslinger is the most impressive-looking game on the Android platform yet, and the demo (pictured) looks great running on the Prime.

On the other hand, Zen Pinball on the Prime features impressive high dynamic range (HDR) lighting, but suffers in frame rate compared with the iPad 2, where HDR is absent. Overall, as impressive as some of the demos are--especially Bladeslinger--there's nothing here so far that looks outside the iPad 2's capability.

Web page loading speeds as well as app download speeds were several seconds slower than on other Android tablets and the iPad 2 in our anecdotal testing. Given our expectations for the effect the Tegra 3 would have on download speeds, this is disappointing.

GPS performance ranged from spotty to good depending on which side of the city (San Francisco) we were in. Performance usually fared better outside, under the open sky, compared with using GPS in our office. We did notice stronger and more connections to satellites when the Wi-Fi adapter was used to augment the performance.

The 8-megapixel rear camera provides the Prime with what is, on paper, the most technically advanced camera we've seen on a tablet. Pictures taken by the camera retained details other cameras like the Tab 10.1's and Sony Tablet S' rear cameras didn't. Colors were slightly lighter than the same photos taken with the Sony Tablet S, but the clarity and overall color accuracy of the Prime's camera make up for this.


An example of the kind of clarity you can expect with the Prime's 8-megapixel camera.

Also, shutter speed on the Prime is nearly instantaneous, whereas the Tab 10.1's camera took several seconds to focus and shoot. Thanks to the 2.4f aperture of the Prime's camera, which allows more light through the lens than is typical for a tablet camera, we were able to see more detail even in low-light situations.

As for moving pictures, 1080p video recorded with the camera is clear and smooth, with no noticeable artifacts like what we saw in the Tab 10.1's 720p videos.

Sound delivered by the speaker carried heavy bass with clarity and thankfully didn't have the "tinny" feel to it that many other Android tablets' sound has. We would have preferred a higher volume, though, as the iPad 2 easily dwarfs it in that department.

With normal use, the battery drained about as fast as on other Android tablets and we were able to continuously use the tablet all day without needing a charge. Here are our official CNET Labs-tested battery life results both with and without the dock connected. More tablet testing results can be found here.

Video battery life (in hours)
Asus Eee Pad Transformer Prime (with dock) 15.3
Asus Eee Pad Transformer Prime (without dock) 9.6

Conclusion
The Asus Transformer Prime is the best full-featured Android tablet yet. Its refined design makes it just as sexy as the iPad 2 or Galaxy Tab 10.1, and the laundry list of thoughtful features, coupled with great video playback and camera performance, deliver an impressive device that more than holds its own against any tablet, including the iPad 2.

While games performance is somewhat of a mixed bag, most of what we've seen is impressive and, in most cases, is just as good as the best of what the iPad 2 has produced. However, it will take some time before developers really dig into the Prime's quad-core guts to produce something that truly blows us away.

The Prime will be available mid-December 2011 at $500 for the 32GB version and $600 for the 64GB version. The dock/keyboard clocks in at $150.

Editors' note: This review was updated with CNET Labs' battery test results.

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