The Nokia Lumia 630 earned itself some stars thanks to its affordable price and vibrant, fun interchangeable plastic back cases. It's 3G only however, which lost it a fair few points. Its twin brother, the Lumia 635 is identical in every respect to the 630, but it comes with 4G LTE on board.
LTE radio aside, the phone is still 4.5 inches, has an 854x480-pixel resolution display, a 1.2GHz quad-core processor, a 5-megapixel camera and runs the latest Windows Phone 8.1 software.
The Lumia 635 is on sale now in the UK for £139 ($238), directly from Nokia. That's only £10 more than its 3G-only sibling -- a remarkably small amount extra to pay -- I'm not sure why anybody would go for the 3G model when 4G will cost you barely any extra.
In Australia, the Lumia 635 has an RRP of AU$279, although Telstra is offering it for AU$240 and, of course, there are multiple carrier plans available. It also sells in the US through T-Mobile and MetroPCS, for about $170 full retail.
Given that both phones are functionally identical, I've done a shorter version of my usual review here -- for the full analysis on display quality, using the Windows software and camera performance, head over to the more comprehensive Lumia 630 review.
Design and display
Like all of Nokia's Lumia phones, the 635 has a plastic, colourful body. The colour comes from the back panels, which curve around the body to meet the display, rather like the iPhone 5C . As well as bright green, you can get the 635 in luminous yellow, orange or black if you're boring. The covers are removable, allowing you to swap them out when you fancy a change or to just replace a knackered old case.
The plastic is sturdy and easily capable of taking a few knocks and bumps, while the toughened Gorilla Glass 3 will prevent the glass front from getting too many scratches from keys in your pocket. It has 8GB of storage as standard, but there's a microSD card slot for you to keep your music, photos and videos on.
The 4.5-inch screen has an 854x480-pixel resolution, which is less than you'd find on the Moto G . Text and images aren't quite as sharp, but it's perfectly adequate for tweeting and Facebook stalking. It's quite bright too and has decent colours. If you want to get the most from your Netflix shows, consider opting for a higher resolution display.
Windows Phone 8 software
The 635 runs the latest Windows Phone 8.1 software, made up of colourful live tiles scattered on a scrolling home screen. It's fun to use and isn't too difficult to get to grips with either -- Windows Phone is a good platform for smartphone beginners. Its downside is that the app store is still quite poorly stocked. Big names like Netflix, Spotify and Skype are present, but it nearly always receives new apps long after iOS or Android. If you're into mobile gaming and checking out the latest app store releases, Windows Phone will not suit.
Nokia has loaded some of its own software on board, including its Here Drive app, which gives turn-by-turn GPS satellite navigation, Here Transit, which provides local information about public transport, including live departures, and Nokia MixRadio, which lets you listen to curated music playlists for free.
Battery life and processor performance
The Lumia 635 has the same 1,830mAh battery as the 630, but with its more demanding 4G LTE radio, I wasn't expecting to see as good battery life. Indeed, on my drain test, the 635's battery level had dropped from full to only 36 percent remaining after three hours of streaming Netflix with the screen on full.
That's a pretty disappointing effort. By comparison, the Lumia 630 had dropped to 73 percent after 2 hours of video looping and 32 percent after 5 hours. It seems that 4G radio has taken its toll. Still, it's a very demanding test and the screen was on max brightness the whole time. If you keep the brightness down and use the phone more cautiously, you should be able to get through a day.
The phone has a 1.2GHz quad-core processor stuffed inside -- again, the same as you'll get on the 630. I found it every bit as adequate as its sibling, providing swift and responsive navigation, and fast camera launch times -- it even handled some gaming.
We tested the Lumia 635 in San Francisco using T-Mobile's LTE network. The diagnostic Speedtest.net results were low and slow, between 2 and 9Mbps down and 5-9Mbps up. While network strength varies by city, keep in mind that the Lumia 635's Category 3 LTE modem is going to be less capable than the Category 4 modem we see in other phones.
According to FCC tests, T-Mobile's Lumia 635 has a digital SAR of 0.61 watt/kilogram.
We tested the call quality for the Lumia 635 on T-Mobile's network in San Francisco. On calls to a landline and a cell phone, our main testing partner noted that voices sounded clear, but had a bit of an echo. On our end, the call sounded clear and natural, without much distortion. The Lumia 635 also did well outdoors, blocking a significant amount of background noise from traffic and even heavy construction so that our partner could here us easily.
The speakerphone on the Lumia 635 didn't work well in testing. Even with the microphone held closely to our mouths, voices sounded far away and flat. Overall, the phone performed well for voice calls, but since call quality depends on network, location, and many other factors, you might experience different results.
On the back of the phone is a 5-megapixel camera, which I found capable of capturing adequate, although hardly outstanding photos. Like most budget phones, it didn't handle low-light well and the auto white balance could sometimes be a little off -- but you can tweak the settings in manual mode.
It's not a phone for the dedicated photographer, but Instagram snaps will be fine.
The Nokia Lumia 635 doesn't have the sort of slick, luxurious design you'd get from a top-end phone, nor does it have a particularly impressive screen or camera, but its cheap price and fun, colourful design makes it a decent choice if you're after 4G on a budget.
If apps are important to you though, take a look at the Motorola Moto G, which is now available with 4G . It's roughly the same price, but you'll have access to a much wider app store that receives new apps far sooner than the Windows Phone 8.1 store, and the screen has a higher resolution.