Smartphone displays have rapidly improved at every single price point. Inexpensive smartphones often compromised on display quality, which ended up hurting much of the overall experience. However, even inexpensive smartphones now ship with IPS displays and high enough resolutions to render text without overwhelming aliasing.

The Lumia 640 has a 5" 1280x720 IPS display. At 294 pixels per inch, it’s fairly sharp for a phone of this price. It’s obviously not some 2560x1440 flagship phone, but I never felt like text appeared fuzzy or highly aliased. To evaluated the aspects of display quality beyond what you’ll see on a spec sheet we turn to our standard smartphone display tests. As always, measurements are performed with X-Rite's i1Pro 2 spectrophotometer and SpectraCal's CalMAN 5 software, with the exception of contrast measurements which are done with an i1Display Pro colorimeter.

Display - Max Brightness

Display - Black Levels

Display - Contrast Ratio

437 nits is a fairly good result for peak brightness. It’s not quite as high as the 500 and 600nit displays that you’ll see on flagship phones, but it’s noticeably higher than many other devices at this price point. The contrast is also pretty good. While the black level isn’t even close to the lowest we’ve seen, when you consider that many devices use CABC to cheat on contrast it’s actually a relatively good result.

Display - White Point

Display - Grayscale Accuracy

The greyscale results on the Lumia 640 are exceptional. RGB balance is great at every shade of grey, with only a very slight shift toward blue. All of the errors will only be visible if you compare static images with a reference monitor. There’s not much more to be said, as the greyscale accuracy on this display is essentially perfect.

Display - Saturation Accuracy

The next test examines saturations of primary and secondary colors on the display in increments of 20%. In this test the Lumia 640 does very well. There are definitely some issues with blue and magenta, and the fact that cyan maxes out at 80% saturation, but the overall accuracy is very good.

Display - GMB Accuracy

The final display benchmark is the Gretag MacBeth ColorChecker test. This test examines colors that are commonly found in the real world, and it’s the best benchmark of display color rendition. A display can hit its saturation targets accurately but fail to reproduce these color mixtures properly.

Fortunately, the Lumia 640 suffers from no such issues. Most of the colors are reproduced with a high degree of accuracy, with the big errors being in shades of blue. Skin tones are very well reproduced, which is something I’ve seen other devices struggling with in recent reviews.

Overall, the Lumia 640’s display is very good, and I would go as far as to say that it’s one of the best displays on a phone at this price point. It performs well in every category, from brightness, to contrast, to color accuracy, and the resolution is high enough to keep everything looking fairly sharp. I think Lumia 640 users will be very happy with the display on their phone.

System Performance Camera Architecture and UX
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  • eanazag - Tuesday, June 9, 2015 - link

    I hated Symbian. Buh-bye Symbian.
  • Callum S - Tuesday, June 9, 2015 - link

    Nice review. I definitely think that it is a fantastic phone for its price.

    I can see how the apps situation for some would be a pretty big concern. As mentioned it is mainly Google and local apps that are missed. However at the same time, for those using Microsoft services, I have found it to be significantly better than Android. Exchange, OneDrive, OneNote and MS Office Apps all work beautifully and the ability to pin the live tiles for each to the home screen has saved myself tonnes of time.

    That blue glossy case - yep, I would probably want to pass on that too. The matte black version is however also available and in my opinion much better.

    I am not too sure about the performance though - especially at the price bracket. After breaking a Nokia 930 I tried to use an old HTC One M7 for a while, before finally buying a Lumia 640, and found the performance of that to be horrible after updating. However perhaps that was due to the HTC sense customisations or something?

    My original intention was to use the Lumia 640 until the Lumia 940 with Windows Mobile 10 is released however I am not too sure I'll be able to justify the upgrade now...
  • Callum S - Tuesday, June 9, 2015 - link

    *HTC Sense customisations
  • Wolfpup - Tuesday, June 9, 2015 - link

    The HTC stuff may not help, but from my experience Android is just dog slow. I've got a Surface 1 running (almost) real Windows 8, and it runs circles around faster ARM hardware running Android, which is just laughable considering how much better Windows is than Android.

    Presumably Windows Phone has even lighter system requirements, so... Although who knows about that, given real Windows is probably optimized out the wazoo, while Windows Phone doesn't get as much attention, but still, my Windows Phones all feel fine, while my android stuff running on anything less than the highest end hardware feels slow.
  • testbug00 - Tuesday, June 9, 2015 - link

    Android runs fine when you don't skin it. Moto G/E use A7 quad cores. I believe the original Moto E used a dual core even.

    And, based on crash reports I've seen, Windows Phone seems to use under 125MB of RAM for the OS.
  • Daniel Egger - Tuesday, June 9, 2015 - link

    Nope, Moto E (2nd gen) runs 4xA53 not A7. Also not to be underestimated the Moto E has a lower screen resolution.
  • mkozakewich - Tuesday, June 9, 2015 - link

    In my experience, a proper operating system like Windows or OS X runs a lot faster than some generic, unoptimised version of Linux. I had a netbook with a quick-boot Linux thing, and I could actually turn off my backlight completely when I used it, but my battery would actually drain quicker than when I'd have the screen on in Windows.
  • leexgx - Thursday, June 11, 2015 - link

    unlike Android it's a requirement that all apps use GPU acceleration under normal use on windows even on old/new crappy 512mb windows phones run Very consistently (more like IOS iPhone/iPad) with Android your having to use Brute force with faster Flash and CPU (android is only been optimised now in 5.0)
  • testbug00 - Tuesday, June 9, 2015 - link

    probably HTC stuff. I have a Moto G (whatever year the original was released in) and it runs Android smoothly. It's a lot weaker than the M7 ;)
  • WorldWithoutMadness - Tuesday, June 9, 2015 - link

    Cmon microsoft, just give us sneak preview of 940 already. I'm sick of this badly chosen hardware budget phone.
    It's not even good enough in super saturated budget phone market in developing country.

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