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Microsoft's Lumia 640 XL gives you more for less. At $249 off-contract, or $8.34 per month on AT&T, this Windows phablet is simply more phone, featuring a 5.7-inch IPS display that rivals similarly sized handsets such as the Nexus 6. It also has a solid 13-megapixel camera for capturing every moment on the fly. However, while this Windows phone looks like a beast upfront, we have some reservations about its battery life and app selection.
Design
You might as well go big or go home when purchasing a phablet, and the Lumia 640 XL fits the bill. It felt like a flat slab of plastic in my hand, with a matte, slightly textured back plate. My review unit had a white back, which stayed pristine for only a few hours before some gray smudges appeared around its edges. (You can also order it in black.) Also on the back is the dime-size camera lens, with a tiny flash bulb above it, and the Microsoft logo in the middle of the rectangle.
The 5.7-inch screen is covered in Corning Gorilla Glass to prevent scratches. After a few minutes of using the Lumia 640 XL, I accepted how cumbersome it felt in my hands because the display was lovely and how easy it was to type with both hands at once.
Although the corners of the Lumia 640 XL are rounded and friendly, its edges are thick. The smartphone measures 6.21 x 3.20 x .35 inches and weighs 6.03 ounces, making it larger than comparably priced Android phones. The $249 OnePlus One measures 6.0 x 2.9 x 0.35 inches and weighs 5.7 ounces and the $249 Alcatel Onetouch Idol 3 measures 6.0 x 2.9 x 0.29 inches and is just 4.9 ounces. To be fair, though, those handsets have smaller, 5.5-inch screens.
Display
The Lumia 640 XL sports a 5.7-inch, 1280 x 720-resolution IPS display, and I found it great for watching YouTube videos and Netflix. While watching all the videos in my subscription feed, skin tones appeared natural and colors were bold. My only issue was that background objects appeared slightly pixelated, especially in dimmer scenes.
The Lumia 640 XL displayed a wide range of hues, registering 113 percent on the sRGB color gamut scale. That beats OnePlus One (92.7 percent) and the Onetouch Idol 3 (93.7 percent). The Lumia's screen is also fairly accurate, as its Delta-E score of 1.6 (0 is best) trumps both the One (8.6) and the Idol 3 (2.55).
MORE: Windows 10 For Phones: Top Features
Where the Lumia 640 XL's display falls short is in brightness - it notched only 329 nits on our brightness test. That's lower than the smartphone category average (388 nits), the OnePlus One (432 nits) and the Onetouch Idol 3 (736 nits).
Software and Apps
Running Windows Phone 8.1 Lumia Denim, the 640 XL and its big display beautifully show off Microsoft's modern design. The home screen has a bunch of Live Tiles that you can resize and move anywhere you want, and they flip and turn periodically, giving the interface a more dynamic feel than Android or iOS. There's only one screen to work with on Windows phones, so I put my most used apps -- including Twitter, Facebook Messenger and YouTube -- at the top so I wouldn't have to scroll to get to them.
Microsoft has some tricks for interacting with Windows phones that make it convenient to use. I loved that I could double-tap the screen to wake up the phone. Combine that with the Glance screen, which adds notifications like weather and a floating clock to your dimmed and locked display, and I rarely had to unlock the Lumia 640 XL to see my most current alerts.
My AT&T review unit came with some bloatware. Out of the five pre-loaded AT&T specific apps, I could see FamilyMap coming in handy for protective parents. A $9.99 subscription lets you keep track of your kids (assuming they're on your plan) viewing the location of their smartphones at any time and receiving alerts when they get home.
Windows Phone still can't compete with the likes of Android and iOS in apps, and that's a major letdown. Popular tools I use every day, like Feedly and Snapchat, aren't available, which severely limited how useful the Lumia 640 XL could be for me.
Performance and Graphics
The Lumia 640 XL is powered by a 1.2-GHz quad-core Qualcomm Snapdragon 400 CPU and an Adreno 305 GPU and 1GB of RAM. There's just 8GB of internal storage, but you can add an additional 128GB via a microSD card. I was able to switch back and forth between apps without any hiccups, although I did occasionally have to wait a few seconds when searching for a topic or Web page in Internet Explorer.
However, the handset did not perform so well on the JavaScript benchmark SunSpider, scoring 1234.3. That's not as good as the smartphone category average of 812.3.
Also, the Lumia 640 XL scored 295 on the Peacekeeper benchmark, which measures overall browser performance. That’s a fraction of the category average of 1,047.
Cameras
The Lumia 640 XL sports a 13-MP rear camera that took lovely, detailed photos indoors and outdoors.
The photos of my desk trinkets featured rich purples and blues, and I could see fine details in tags and fur on stuffed animals.
Outdoor photos were bright and true-to-life colors, and I could see even the smallest detail in hand-painted wooden doors clearly.
The rear camera also handled low-light situations well, both with and without flash on. Small nuances in clothing and facial features were crisper with the flash turned on, but photos still came out fairly bright even with the flash disabled.
The 5-MP front camera didn’t fare nearly as well. It rendered my selfies with splotchy facial features, a slightly yellow tint to my skin and fuzzy details in my hair. Also, both cameras took at least three seconds to capture and save a photo to the gallery, forcing me to stop and wait to take the next photo.
Battery Life
While we couldn’t run our standard battery test on the Lumia 640 XL, its removable 3,000 mAh battery lasted 7 hours and 12 minutes when streaming a video from YouTube over LTE with the screen set to medium brightness.
On our standard test (Web surfing over LTE at 150 nits), the average smartphone lasted (8:28), the OnePlus One lasted 13:16, and the Onetouch Idol 3 lasted 9:16.
MORE: Smartphones with the Longest Battery Life - Tom's Guide
Bottom Line
Anyone who likes Windows Phone and has been dying for a huge canvas with which to use it will like the Lumia 640 XL. Its 5.7-inch display shows off the Live Tile interface of Microsoft's mobile operating system well, and makes it easier to do things like type messages and notes, as well as watch videos and view photos. The biggest drawback is its below-average battery life. If you want a smartphone that lasts all day and provides better overall performance, we'd recommend the $249 OneTouch Idol 3. But the Lumia 640 XL is a solid phablet for Windows Phone enthusiasts.
Valentina Palladino is a senior writer at Tom’s Guide. When she’s not writing about fitness trackers or phones, she’s probably at a concert, or shopping at a beauty supply store. Follow her on Twitter at @valentinalucia.
