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Android Curveball: LG G Flex Review
Date: Feb 26, 2014
Author: Jennifer Johnson
Introduction and Specifications

LG’s new G Flex smartphone is the “world’s first curved flexible smartphone” according to the company. We’ve seen smartphones that have curved bodies before, but this is the first smartphone to feature a display and battery that are curved as well. LG claims the curved design of the G Flex is optimized for the average face to provide better call and sound volume quality. For users who are going to put the phone in their back pocket, the curved shape of the phone also makes it fit more comfortably.

In addition to its curved form, there’s one other very noticeable feature of this smartphone, and that’s its large 6-inch display. If you set this phone next to any average-size smartphone, there’s no mistaking the G Flex offers a LOT of screen real estate. Another differentiating factor of the G Flex is its Rear Key and volume controls. In other words, there are no hardware buttons on the front of the device. The Rear Key and volume rocker are located below the camera on the back and are easily located by touch alone.

In an effort to take full advantage of the G Flex’s large display, LG is also including a number of unique software features with the device that are designed to give the user greater multitasking functionality. We’ll take a closer look at all of these features in the coming pages.

LG G Flex
Specifications & Features

Snapdragon 2.26 GHz Quad-Core Processor MSM8974
32 GB (Up to 24 GB for User Memory)

Size & Weight
6.32 (H) x 3.21 (W) x 0.33 (D) inches
6.24 ounces

6.0-inch Curved HD OLED Screen with Corning Gorilla Glass 2 (1280 x 720)
Android 4.2.2 (Jelly Bean)
SIM Card Type
micro SIM
Sprint Frequencies: GSM 850/900/1800/1900 MHz, UMTS
850/1900/2100, LTE Bands 25/26/41
Sprint Data Transmission: GPRS, EDGE, UMTS, HSPA+, WCDMA, LTE
802.11 a/b/g/n/ac
Bluetooth 4.0 LE
SmartShare Beam

Software Features
Dual Window, Slide Aside, QSlide, QuickMemo, KnockON, Quick Translator, On-Call Notes, Polaris Viewer 5, QuickTheater, QuickRemote, VuTalk, Guest Mode, & more
13 Megapixel Rear-Facing Autofocus Camera with LED Flash
2.1 Megapixel Front-Facing Camera
3,500 mAh
Talk Time: Up to 29 Hours

Sprint $149.99 - $179.99 with discounts and contract
AT&T $149.99 - $199.99 with discounts and contract
T-Mobile $672 full retail price


We’re testing the Sprint version of the G Flex in this review. But LG has also teamed up with AT&T and T-Mobile to offer the device. Before we dive into the full hands-on review, take a close look at the specifications above.


The LG G Flex has a large, 6-inch curved plastic OLED display that sports a resolution of 1280 x 720. By using a plastic OLED instead of a glass OLED, LG was able to make the panel bendable, thinner, lighter, and not easily breakable. To improve the image quality and clarity, LG used a Real RGB Stripe Pixel structure instead of a Pentile method. In comparison to screens with a Pentile OLED, the G Flex’s Real RGB stripe of sub-pixels is able to produce brighter and more accurate images with better color expression and a more genuine white color.

In real life, the G Flex’s display looks good. However, when placed next to the HTC One Max (which supports 1920 x 1080) with both screens at 100% brightness, the One Max’s higher resolution display offers a very noticeable difference in clarity and crispness of text.


The G Flex has a 700R (700mm radius) curvature that was selected after consumer research and testing. Interestingly enough, when holding the G Flex to our ear, it did feel slightly more comfortable than holding the similarly sized HTC One Max. When holding the HTC One Max in your hand, you get a feel that you’re holding a very sturdy, oversized smartphone. When holding the G Flex, the curved design and plastic body gives it a softer feel than the One Max. We preferred the feel of the G Flex in hand over the One Max since the G Flex didn’t make us feel like we were holding a monster-sized smartphone.

LG includes a durable coating on the back cover of the G Flex to help make the device more scratch-resistant from the everyday nicks of life that would normally occur while the phone is in a person’s pocket. Keep in mind however, that this coating is not designed for intentional scratching. This cover is smooth and doesn’t provide a lot of grip when you’re handling the phone.

In order to enable the curved design of the G Flex, LG developed a 3,500mAh curved battery. This battery is designed using LG Chem’s Stack & Folding technology. In order to offer stability and prevent distortion, LG embedded this battery. LG Chem also applied its SRS (Safety Reinforcing Separator) technology to help ensure battery stability and durability.

Initially, we had mixed feelings about the placement of the Rear Power Key. Although it can be very easy and convenient to use while holding the phone, it can be easy to push the Rear Key accidentally and turn off the display. While holding the G Flex to our ear, we found ourselves resting our index finger on the Rear Key. As long as you’re careful not to push this key while talking, there shouldn’t be any issue. While pinching the phone between our shoulder and ear, we pushed the Rear Key a few times, however.

After a spending a few days with the G Flex, we had become accustomed to using the Rear Key and our accidental presses were much less frequent. In fact, after a few days of use we actually grew to like the Rear Key placement in many situations.

The placement of the volume rocker on the back of the G Flex makes it very easy to adjust during a call. By long-pressing the volume up key, you can launch QuickMemo. A long press of the volume down key will launch the camera. When using the camera app, the settings menu gives you the option to control the zoom or shutter using the volume keys. By default, the volume keys will control zoom.

Above the display, you’ll notice the front-facing camera, proximity sensor, and notification LED in the upper left corner. When the screen is on, you’ll see an app launcher at the base of the Home screens as well as Back, Home, and Menu keys at the bottom of the display. On the back of the G Flex, you’ll find the 13 megapixel camera. An IR LED is located to the left of the camera and a flash is located to the right of the camera. Below the camera you’ll see the Power/Lock button which is surrounded by the volume keys. A speaker is located in the bottom right corner of the back of the phone.

The lower edge of the phone houses the microUSB charging port, microphone, and 3.5mm headset jack. On the left edge of the phone, you’ll find the micro SIM card tray.

User Experience

In addition to the standard features and functions we’ve come to expect on a smartphone, LG has included a number of extra features, apps, and functionality. Let’s take a closer look at some of these extras.

LG’s dual window mode lets you divide the screen into two separate windows for multi-tasking. Given that the G Flex has a large 6-inch screen, this multitasking functionality is an ideal add-on. Press and hold the Back button to enable Dual Window and select the applications you want to use with this feature. Initially, the windows will be split 50/50 but you can resize as you see fit.


LG G Flex applications

If you have the Slide Aside Multitasking feature enabled, you can also use a three-finger swipe to save running apps to the left or bring them back to the display. Slide Aside can hold up to three applications. When using Slide Aside, you’ll see a small indicator in the upper left corner of the screen that tells you how many apps are open. When multiple apps are open and you use three fingers and slide to the right, you’ll have an option to close open apps by swiping up or pressing the X button.

We saw LG’s QSlide functionality on the Optimus G Pro, and we were pleased to see it again on the G Flex. This feature lets you have multiple apps open at the same time, similar to how you would in Windows on a desktop or laptop computer. With the G Flex, we’re seeing even more QSlide compatible apps than before; now this functionality is available with Videos, Phone, Messaging, Calendar, Email, Memo, Voice Mate, File Manager, and Calculator. You can move QSlide apps around the screen and resize them. You can also adjust the transparency of these apps.

Another handy app that is making its return on the G Flex is QuickMemo. This app lets you capture screen shots, write on any screen, create memos, and share images you've created. You can easily access QuickMemo by dragging your finger down from the top of the screen and selecting QuickMemo.


DualWindow and QSlide

LG also includes an Urgent Call Alert feature that will make the front indicator LED and the Rear Key flash red if you’ve missed several consecutive calls from the same person. This can be especially useful if you’re in a meeting and can’t answer your phone but want to know at a glance if a call is urgent.

Using Guest Mode, you can set different lock patterns for owner and guest modes. When you unlock the phone under Guest Mode, only applications and content that has been pre-approved by the owner will be visible. Guest Mode can be enabled using the Settings menu after you’ve selected Pattern for Screen Lock. If you have coworkers or kids who regularly use your phone, Guest Mode is a great way to keep them out of certain areas and important documents while still letting them play games and enjoy content on your phone.

Users can quickly turn the G Flex screen on and off by tapping on the screen twice. This is particularly useful if you have the phone sitting on your desk and want to look at something without having to pick up the phone, hit the Rear Key, and set the phone back down. There is a slight delay in powering the screen on using this Knock feature but it works well overall. You can turn off the screen in the same manner by double-tapping the screen in the status bar, an empty area of the Home screen, or from the Lock screen.


Guest Mode, Slide Aside, and Translate features

QuickRemote can control a variety of IR devices including fans, televisions, DVD players, and more. You can customize QuickRemote by mapping buttons from a remote to the application. Answer Me is a feature found on the G Flex that lets you answer phone calls simply by placing the phone to your ear.

A launch bar is located at the base of all home screens. You can customize this launch bar to your liking. It can hold up to seven icons, though one of these icons must be the Apps icon. You can also group apps on the launch bar into a folder. You’ll find the Back, Home, and Menu keys below the launch bar.

From the lock screen, you can add links to a number of different applications making it quick and easy to open what you want directly from the lock screen. If you hold the phone in landscape mode, you can touch the screen and drag outward with both thumbs to open QuickTheater, an app that offers one-touch access to photos, videos, and YouTube.

Camera and Battery Life

The LG G Flex incorporates an improved camera module that features a larger image sensor. As a result, LG claims the G Flex’s camera is better suited to take brighter photos since it can absorb more light.

Some of the camera features include HDR technology, face tracking, Cheese shutter, VR panorama, Dual camera, Time catch shot, and more. While using the camera, you may notice the LED light on the Rear Key changes colors. When Face Tracking is enabled, you’ll notice a yellow light while the camera is focusing and a green light when the camera is properly focused. If you’re using the timer feature, the LED will blink blue as the countdown for the timer begins. The blinks will become faster and turn red before the photo is taken.

During our tests, we felt the LG G Flex did a very good job at capturing images. On multiple occasions we noticed that if we took two sequential pictures of the same subject the focus and crispness of the second photo was much better than the first, especially when shooting subjects that were within a close range of the lens. Landscape photos showed good depth.


Battery Life

You’ll find a 3300 mAh embedded Li-polymer battery inside the LG G Flex. Talk and standby times vary on the G Flex depending on which carrier’s phone you have. Our Sprint version is rated at up to 25 hours of talk time on 3G and up to 585 hours of 3G standby time.

In an attempt to quantitatively measure the G Flex's battery life in a controlled benchmark environment, we ran the AnTuTu Battery Test which is available from the Google Play Store. For this test, we set the G Flex's display to 50% brightness, which is still plenty bright and easy on the eyes. The G Flex scored 575, earning it the second spot in our chart behind the HTC One Max. Although we always like user-replaceable batteries in phones, the longevity of the G Flex should eliminate the need to swap batteries for most users.

During our real-world testing, the G Flex had no problem making it through a day while checking emails, making calls, taking pictures, and playing a few games. We would expect an average user should have no problem making it through an entire day with moderate use as well. Of course, battery life will vary depending on how the phone is used.

Performance: CPU and Device

Next, we'll take a look at how the LG G Flex compares to other smartphones by examining a few benchmarks that are currently available in the Android Marketplace.

CPU testing
Android CPU testing

AnTuTu benchmark – click to enlarge

AnTuTu’s latest benchmark returns a number of scores—too many to graph so we’re including a look at all the numbers in a table. The G Flex earns second place in four categories: Database IO, Storage IO, GPU (3D), and RAM (Speed). It earned first place in the UX Runtime test.

Mobile XPRT Benchmark Tests - Click to enlarge

The MobileXPRT benchmark runs through a variety of tests to evaluate the responsiveness of a device along with its ability to handle many everyday workloads.

The G Flex wasn’t a top performer in the MobileXPRT tests. Comparatively speaking, the phone achieved its best score in the Apply Photo Effects test where it earned third place. In both overall scores, the G Flex came in fifth place out of the eight devices we have for comparison.

Performance: GPU

Graphics testing
Android graphics testing


GFXBench has been one of our standard graphics performance benchmarks for a while. Recently, the company updated its software to version 3.0. With this new version, the old tests are no longer available to run for comparison. Still, we were able to round up a handful of phones to give you a feel for how the LG G Flex stacks up.

As you can see in the T Rex 1080p test, the G Flex earns the top spot by a comfortable margin. In the offscreen fill test, the G Flex still performs well, earning the third spot behind Samsung’s Galaxy Note 3 and Google’s Nexus 5.

In Basemark X, the G Flex earns the third spot in both the on-screen and off-screen tests. Upon examining the scores a bit more closely, you may notice that the G Flex outperforms the Galaxy Note 3 in the on-screen test but the reverse is true in the off-screen test.

As is the case with other high-end devices, 3DMark Ice Storm is maxed out at lower settings on the LG G Flex. Running the test on Unlimited mode yielded excellent results, with the G Flex earning the second or third spot in all tests.  

Performance: Browsing and JavaScript

Next up, we have some numbers from the SunSpider JavaScript benchmark. According to the SunSpider website:

This benchmark tests the core JavaScript language only, not the DOM or other browser APIs. It is designed to compare different versions of the same browser, and different browsers to each other. Unlike many widely available JavaScript benchmarks, this test is:

Real World - This test mostly avoids microbenchmarks, and tries to focus on the kinds of actual problems developers solve with JavaScript today, and the problems they may want to tackle in the future as the language gets faster. This includes tests to generate a tagcloud from JSON input, a 3D raytracer, cryptography tests, code decompression, and many more examples. There are a few microbenchmarkish things, but they mostly represent real performance problems that developers have encountered.

Balanced - This test is balanced between different areas of the language and different types of code. It's not all math, all string processing, or all timing simple loops. In addition to having tests in many categories, the individual tests were balanced to take similar amounts of time on currently shipping versions of popular browsers.

Statistically Sound - One of the challenges of benchmarking is knowing how much noise you have in your measurements. This benchmark runs each test multiple times and determines an error range (technically, a 95% confidence interval). In addition, in comparison mode it tells you if you have enough data to determine if the difference is statistically significant.

JavaScript testing
JavaScript Android and iPhone testing

The G Flex comes in just behind the Galaxy Note 3 in this test. Considering the Galaxy Note 3 earns the best SunSpider score from an Android-based smartphone, the G Flex’s score is very good.

Rightware Browsermark
Web Browsing Performance

In Rightware’s Browsermark test we see very similar results as we did with the SunSpider test where the G Flex comes in behind the Samsung Galaxy Note 3 and earns a very solid score.


There’s no doubt the LG G Flex is a unique smartphone. Not only does it have one of the largest displays on the market, but this phablet also has a curved form that really sets it apart. Overall, we were surprised at how comfortable the G Flex felt in the hand. And for a device that has such a large footprint, it didn’t feel any heavier than an average smartphone.

LG equips the G Flex with a number of features that make it stand out in the crowd. The most obvious are its curved display and larger battery. The fact that LG had to put extra time, effort, and research into making a curved display and battery that could withstand everyday use shows the company is working hard to differentiate, which is vitally important in the crowded smartphone market.

LG G Flex - $149.99 On Contract

LG is also taking a different approach from traditional smartphones by placing the volume rocker and Rear Key on the back of some of their flagship phone. We had our reservations about this placement at first but after regular use, we found it to be quite comfortable and easy to use, especially given the size of the phone. In many ways, the Rear Key was more usable than a Power key located elsewhere because it was easy to find and access while holding the phone. The fact that LG lets you wake the phone by tapping the screen also helps user  to not miss a traditional Power key located on the edge of the phone.

On the software side, LG offers a number of apps that add to the utility of the device. We were particularly fond of the multitasking capabilities that come through Dual Window mode and Slide Aside Multitasking. Guest Mode is another feature we really liked. Although the feature is designed to make it easy for you to let someone else use your phone, it also could work great as a kid-friendly mode. We wish more phones had this functionality.

We also appreciated the way in which LG uses the LED indicators on the front and back of the phone. For example, if you’ve missed several consecutive calls from the same person, the LED on the front and back of the phone will let you know. In camera mode, the rear LED can let you know when the camera is about to take a picture in timed mode or if the camera is in the process of focusing or already focused using Face Tracking.

In terms of benchmark scores, the LG G Flex earned consistently good scores in all tests. Although this phone didn’t take the No. 1 spot in every test, it’s still a phone that should be respected for its ability to perform.  It's also reasonably priced for $149 currently on contract with AT&T and Sprint.

Bottom Line: Users who are considering a large-screen phablet device should definitely put the LG G Flex on their short list for devices to consider. This phone offers great performance along with a number of key features that result in a premium experience all around.


  • Excellent multitasking features
  • Curved 6-inch display
  • Great battery life
  • No microSD card slot
  • 720p display rather than 1080p
  • Fixed battery

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