Xiaomi Redmi K20 Pro/Mi 9T Pro review

Display

The Redmi K20 Pro packs a 6.39" Horizon AMOLED, also called Super AMOLED, meaning Samsung makes it. It is not disturbed by a notch, and the only things eating some pixels are its rounded corners. The resolution of the panel is very common - 2,340 x 1,080 pixels (403ppi) - meaning a 19.5:9 screen aspect ratio.

The 6.39" 1080p+ AMOLED has become the most common screen on the market nowadays, notch or no notch. They all have a Diamond PenTile subpixel arrangement on their pixel matrix, and the K20 Pro screen is no different.

The K20 Pro OLED supports HDR10 content and fully covers the DCI-P3 color space. It is protected by a Gorilla Glass 5.

The screen has an excellent brightness for an OLED panel of 450 nits - that's in line with what Xiaomi promises (430 nits). But it can go as high as 643 nits in bright light if you leave it on Auto, also matching and even exceeding Xiaomi's official promise for 600 nits.

The minimum brightness when displaying purely white color was 2.2nits - pretty impressive.

Xiaomi offers three different Contrast settings, each one representing a specific color space. The Automatic contrast fully covers the DCI-P3 color space, and we measured an average deltaE of 3.8. Only in this mode, you can choose the color saturation (default, warm, cool) and the deltaE of 3.8, which we measured was taken at the default preset. Choosing Warm will offer an even more accurate presentation with an average deltaE of 2.5.

The Standard Contrast corresponds to sRGB, and we also recorded an average deltaE of 2.4 for the color accuracy, meaning it's a pretty great one.

Finally, the Increased Contrast makes the colors pop and they are no longer as accurate.

Battery life

The Xiaomi Redmi K20 Pro is powered by a 4,000mAh Li-ion battery. It supports Quick Charge, and the supplied 18W charger fills about 50% of a depleted battery in 30 mins. A full charge takes about 100 mins. We tried charging the phone with Xiaomi's 27W charger we had lying around, but it did not charge the battery faster than the supplied one.

The Redmi K20 Pro scored an excellent endurance rating of 103 hours and had great times across the board. The screen-on times are fantastic - we measured 13 and a half hours runtime in our web browsing test and north of 20 hours in our video playback test.

The standby performance was better on the Mi 9T/K20 when compared to the Pro model here, probably meaning its Snapdragon 855 modem is less power efficient in standby than the K20's S730.

Our battery tests were automated thanks to SmartViser, using its viSerDevice app. The endurance rating above denotes how long a single battery charge will last you if you use the Xiaomi Redmi K20 Pro for an hour each of telephony, web browsing, and video playback daily. We've established this usage pattern so that our battery results are comparable across devices in the most common day-to-day tasks. The battery testing procedure is described in detail in case you're interested in the nitty-gritty. You can check out our complete battery test table, where you can see how all of the smartphones we've tested will compare under your own typical use.

Speaker test (old, new one below)

There's a single bottom-firing loudspeaker on the Redmi K20 Pro. It is quite loud and scored an Excellent mark on our test. The output is also very good - there is rich sound, but there are some high-pitched notes that come out wrong at maximum volume, and this keeps us from giving it an excellent mark for quality of output.

Speaker test (new)

Use the Playback controls to listen to the phone sample recordings (best use headphones). We measure the average loudness of the speakers in LUFS. A lower absolute value means a louder sound. A look at the frequency response chart will tell you how far off the ideal "0db" flat line is the reproduction of the bass, treble, and mid frequencies. You can add more phones to compare how they differ. The scores and ratings are not comparable with our older loudspeaker test. Learn more about how we test here.

Audio quality

The Xiaomi Mi 9T Pro did well with an active external amplifier. With super high volume and top marks for clarity, it properly aced the first part of the test.

Headphones dropped the volume a bit, but the Mi 9T Pro remained louder than most smartphones out there. The accuracy of the reproduction took a much bigger hit with stereo crosstalk and intermodulation distortion worsening significantly and frequency response going a little shaky. So while the Mi 9T Pro does have the power to drive high impedance headphones to significant levels of loudness, it won’t necessarily be the best experience.

Xiaomi Mi 9T Pro frequency response

You can learn more about the tested parameters and the whole testing process here.