gadgets microsoft reviews

Lumia 635 Review

The rise of the smartphone has been meteoric, and while many have been designed and priced in the image of the aspirational iPhone, sold in developed markets, it’s the entry price segments, in developing markets, that have powered the vast majority of expansion in the past couple years.

Windows Phone has faced massive adoption challenges, but one area where it has seen some success is in the entry segment, sub-$150 devices, often sold in developing markets or other markets where subsidies are not a major part of the telecom ecosystem. Take a look at the Lumia 520, a ~150USD open market device. It holds approximately 1/3 of the entire Windows Phone market. And that’s not simply in emerging markets; in significant parts of the EU and the United States, the same holds true.

Lumia 635

For Windows Phone 8.1, Nokia is in the midst of refreshing its series of phones, and appropriately, they’ve started with the entry segment. The Lumia 635 is one of the lowest cost LTE devices on the market (189USD open market) and its triplet siblings, the 630 and 630 dual SIM, are even lower in price, trading off LTE support for a lower price point. In North America, the Lumia 630/635 has shown up on a number of carriers at very reasonable price points. Having a soft spot for cheap and cheerful smartphones and wanting to see how things were in the budget Windows Phone world, I purchased one. They’re $99 and 129 at the Microsoft Store, no-contract, on AT&T and T-Mobile, respectively. I got the T-Mobile version. Here are some thoughts on how things are looking for the future of smartphones.

Lumia 635

I currently use a Lumia 1520 as my primary device. There have been many times where I wished for a smaller phone. The Lumia 635 has a 4.5″ display, with okay bezel sizes, wrapped in a polycarbonate casing. From a dimensions perspective, it doesn’t stand out either positively or negatively. Reaching to the corners of the display, with a single hand, isn’t a problem. The corners are rounded and the sides taper, so in-hand, it’s comfortable. It slips into pockets without any issue. Physical buttons are arrayed on the right-hand side, per usual for Lumias. Missing, from the usual complement, is a dedicated camera button.

The back cover, on the T-Mobile version, is a pleasant matte white. The shape and design are unassuming, but in person, look clean and simple. And, if you want a dash of boldness, you can buy colored covers (I’ve seen yellow, green, and orange). Even better, as the casing wraps around the edges and front of the phone, you could do quite a lot of damage to and then easily refresh it. The covers are priced reasonably – $15 each. The cover is a bit challenging to remove, until you get the hang of it, after a few tries. The benefit is a tight fit, with no creaking nor flexing. The replaceable battery, microSIM and microSD slots are hidden beneath the cover; in all cases, the battery must be removed to swap SIMs or microSD.

Lumia 635 back

Compared to another budget phone I’m familiar with, the Moto G, the in-hand feel is a trade-off – the G has a better form-fitting shape, but the materials feel cheaper (smoother and slipperier).

The display is adequate for the price, with an 854×480 resolution. The additional vertical pixels are used for on-screen soft-keys, a first for Windows Phones, but part of a strategic bet to close the gap with Android phone hardware requirements. Gorilla Glass 3 protects the display, and Nokia’s ClearBlack technology helps reduce reflections and increase contrast. It’s not hard to see some pixelation at normal viewing distances, but in typical use, the UI elements are not filled with so much fine detail to expose the issue, and forgivable at its price point. More challenged is the display’s ability to render text on a full website, zoomed out (or otherwise fine text and details). You really can’t read it, without zooming in. The 720p display of the Moto G would obviously be preferred, but I suspect we’ll soon see something in the Moto G LTE’s price range with a similar display from Windows Phones.

There is no front camera (unfortunate for selfi-ers and those who want to use Skype) and the rear 5MP is nothing to write home about. It takes adequate photos in good lighting, and quickly falls off after that. Nokia’s excellent camera app is still preinstalled, so you can tweak and tune every setting as you could on a higher-end PureView device. Take a look at the result.

Lumia 635 camera sample

Capabilities and Experience

I won’t ramble too much on the rest. The software experience and feature set is as you’d expect to find on most Windows Phones, with a few things to note:

  • It ships out of the box with Windows Phone 8.1 and the Lumia Cyan feature pack from Nokia (Microsoft)
    • Given it’s a Lumia, it comes with a number of useful inbox apps, including Here Drive+, providing free offline navigation in many countries
  • It includes a trio of soft-keys for Back, Windows Home, and Search
    • However, the nifty capability to show/hide them on the Windows Phone HTC One is missing here. Hopefully this changes in future 8.1 updates.
  • It’s missing several hardware-driven features:
    • No front-facing camera
    • No ambient light sensor to automatically adjust display brightness (means you need to leave display brightness as 1-of-4 shortcuts in Action Center)
    • No proximity sensor to turn your display off during calls (uses the capacitive touchscreen, instead to do the same)
    • No physical camera button
  • It supports SensorCore, which is a new SDK that enables very low power sensor data collection, particularly while the display is off.
    • One basic capability is to report steps, providing pedometer functionality, but has many other use cases, as well, such as identifying when the user is near a well-known location.
    • The step-counter in the Bing Health and Fitness app is pretty accurate. It’s within +/- 5% of what my Fitbit Flex reports, on an average daily basis.
  • It supports WiFi calling on T-Mobile
    • My apartment doesn’t get a strong T-Mobile signal, so WiFi supplements
    • While I’m traveling internationally (such as right now, to Canada), calls and texts back to the United States are free on WiFi – nice
  • It has 8GB of internal storage, expandable via a microSD card, and 512MB RAM
    • Approximately 3.3GB are used for system files and another ~500MB are taken up by inbox apps
    • The device starts with ~3.5GB of free space on the internal storage

I can live with almost all these trade-offs, to get to this price point (adaptive display brightness, supported by an ALS, is greatly missed). However, the single most significant factor contributing to its budget-phone experience is the inclusion of 512MB RAM. There are a number of apps in the Windows Store (particularly in the games category) for which 512MB RAM does not meet minimum requirements, and hence cannot be installed on the 635. I don’t play any serious games on my phone, so that means little to me.

The more impactful, day-to-day, symptom is the number of “Resuming…” messages you’ll see, as you multitask across apps. With 512MB RAM (versus 1GB+ on the higher end Windows Phones), fewer apps can be kept in the backstack, warm in memory, before critical limits are hit and app contents needs to be ejected. This means a rehydration is needed, when you go back to that particular app. The app platform and apps themselves have done a pretty good job of maintaining state, even across rehydrations, but it still results in an extra second or two to load most apps. Many of the inbox experiences are, thankfully, relatively resource friendly, and launch quickly.


In a vacuum, there are a few compromises I would not have made, 512MB RAM, lack of an ALS, but hitting a ~$170 transfer price for an LTE phone, in North America, is non-trivial. Even more so, the $99-129 end-user price on pre-paid service is nearly irresistible. It’s a well-built, well-featured, simply designed phone that delivers all the smartphone a basic user needs. It’ll look fresher, while offering similar or better capabilities than the equivalently priced Android prepaid phone around most carrier stores. It definitely meets the bar of a cheap-and-cheerful, tossable phone, and should do well, both on prepaid service in developed markets, while providing a quality option for developing markets, moving towards LTE deployments.


  • Looks simple and sleek, feels nice to hold
  • In-app experiences are smooth and fluid
  • SensorCore support provides a free and accurate pedometer (amongst other capabilities)
  • 8GB internal storage will be enough for many, and good support for microSD expansion makes it a complete non-issue
  • One of the better (best?) combinations of form factor, build quality, performance, feature set and LTE support for the price


  • Not an ideal choice for heavy multitaskers with 512MB RAM and “Resuming…” pauses
  • No ambient light sensor for auto display brightness adjustments
  • No front-facing camera for Skype
  • Display resolution is a bit below average, especially depending on regional pricing (in the US, it’s average)

Lumia 635 and 1520 Comparison