ASUS Zenfone 9 review: Great things come in small packages

The Zenfone 9 delivers a well-rounded feature-set in a small package.

ASUS Zenfone 9 review
(Image: © Harish Jonnalagadda / Android Central)

Android Central Verdict

The Zenfone 9 is a small phone with huge potential. The diminutive design makes it ideal for one-handed use, and it has the same caliber of hardware as $1,000 flagships. The 120Hz AMOLED screen is a joy to use, the Snapdragon 8+ Gen 1 is the fastest chipset you'll find today, the cameras are phenomenal, and the battery lasts two days on a full charge. Combine that with an IP68 rating, 3.5mm jack, and clean software without any bloatware, and you get the best small Android phone money can buy today.

Pros

  • +

    Designed for one-handed use

  • +

    Incredible performance

  • +

    Sublime 120Hz screen

  • +

    Vanilla Android UI with zero bloatware

  • +

    Great cameras

  • +

    IP68 dust and water resistance

  • +

    Loud stereo sound, 3.5mm jack

  • +

    Battery lasts two days with ease

Cons

  • -

    Only two Android version updates

  • -

    No wireless charging

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ASUS offered two models in the Zenfone series last year: the standard Zenfone 8 was aimed at those looking for a small phone, and it was joined by the Zenfone 8 Flip that had a 6.67-inch panel and 5000mAh battery. This year, however, ASUS is going all-in on the small form factor, launching just a single variant of the Zenfone 9 that focuses on one-handed usability.

To that effect, the Zenfone 9 is a little narrower and shorter than its predecessor, making it the ideal device for one-handed use. At the same time, ASUS retained the same 5.9-inch 120Hz screen, somehow increased the battery, and added huge camera modules at the back and a thermal cooling layer that's in line with that you'll find on $1,000 flagships.

ASUS hasn't removed any features either; the Zenfone 9 still has IP68 dust and water resistance, great stereo sound, and there's even a 3.5mm jack. And on the hardware side of things, it features Qualcomm's latest Snapdragon 8+ Gen 1 platform. The small flagship category has constricted in recent years, but with the Zenfone 9, ASUS has delivered a device that raises the bar for this segment.

About this review

I'm writing this review after using the Zenfone 9 as my daily driver for ten days in Hyderabad, India. I'm using the 16GB/256GB version of the phone, and it runs Zen UI based on Android 12 along with the June 2022 security update. It received an OTA update out of the box to build 32.2004.2004.78, and a further update on the day I'm publishing this review (July 28) to build 32.2004.2004.84 containing stability and bug fixes alongside camera tweaks. ASUS provided the unit to Android Central for review.

ASUS Zenfone 9: Price and availability

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

ASUS unveiled the Zenfone 9 on July 28, 2022, and the phone will go up for sale in August. It will debut in Taiwan, Hong Kong, and Europe initially, where the Zenfone 9 will cost €799 ($815). Like last year, ASUS will introduce the Zenfone 9 in the U.S., but the brand didn't reveal a launch date as of yet. The good news is that the phone will launch for $699 in the U.S., making it that much more affordable.

The Zenfone 9 will be sold in three configurations: a base model that comes with 8GB of RAM and 128GB of storage, an 8GB/256GB version, and a 16GB/256GB edition. The last variant seems overkill given you don't need 16GB of RAM, and it would have been better to see a 512GB storage variant instead. You can choose between four interesting color options this time around.

ASUS Zenfone 9: Design

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

There's a clear shortage of short phones with flagship internals, and that's the area ASUS is targeting with the Zenfone 9. As such, you get a diminutive design that makes other compact devices like the Pixel 6a and Xiaomi 12 Lite look huge. The Zenfone 9 is smaller even than its predecessor, with dimensions of 146.5 x 68.1 x 9.1mm.

The Zenfone 9 is diminutive next to other Android phones, but it isn't missing out on any features; you even get a 3.5mm jack here.

What this means is that the Zenfone 9 is an absolute joy to use one-handed. It's 2.5mm narrower than the Galaxy S22, and the difference is noticeable in daily use. It is 1.5mm bulkier, but on the plus side, you get a large 4300mAh battery. And while most small phones tend to be focused on the mid-range category, that isn't the case with the Zenfone 9 — this is one of the fastest phones you can buy today.

A key difference from last year is the switch to a rectangular design with flat sides; ASUS noted that this was the best way to maximize the internal volume. While I'm not a fan of this trend, I didn't have issues on the Zenfone 9; for one thing, the phone's dimensions ensured it nestled easily in my hand, and there's a subtle curve where the back meets the mid-frame, and that makes a sizeable difference with the in-hand feel.

ASUS went with an aluminum mid-frame that has a matte finish, and it's great to hold and use. As for the design at the back, two things stand out: a gigantic camera housing that takes up a significant chunk of room, and a new textured material that feels much better than polycarbonate. Although the device is using a metal mid-frame, it comes in at 169g, and that's thanks to the new polymer material used at the back.

The Zenfone 9 has a quirky design, but it is fantastic to hold and use one-handed — ASUS did a great job.

Let's talk a little bit more about that camera housing, because it is one of the largest I've seen on a phone this year. The Zenfone 9 has two cameras, each ensconced within its own ring, and the main 50MP module protrudes quite a bit from the body of the device, making it wobble on a flat surface.

I'm no stranger to using phones with bulky camera designs — I used the Xiaomi 11 Ultra for several months last year — but the sheer size of the modules here makes them seem out of proportion with the rest of the device. This is because ASUS went with large cameras and gimbal stabilization tech; a first for the manufacturer. The result is that the two cameras take up an inordinate amount of room at the back.

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

The design for the camera housing may not be to everyone's liking, but ASUS nailed the rest of the design brief. The polymer material that ASUS designed for the back is 36% lighter while still delivering excellent grip, and the finish ensures it's easy to hold. That said, the black color variant isn't quite as effective at hiding smudges or scratches, and you should consider one of the other colors if you intend to use the Zenfone 9 without a case.

There's good news on that front, as ASUS is offering the Zenfone 9 in four color variants: Midnight Black, Moonlight White, Starry Blue, and Sunset Red. The red and blue options in particular look incredible, and that would be the way to go for this device. The material itself isn't as immune to scratches as glass, but ASUS says that it should be more durable.

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

Another area where ASUS switched things up this time is biometrics. The Zenfone 9 has a side-mounted fingerprint sensor in lieu of an optical in-screen module like last year's Zenfone 8. My only issue with it is that it's positioned slightly lower than where my thumb usually rests when using the phone one-handed, and it would have been better to just have the power button on the right and the volume rocker on the left.

That said, the sensor itself is noticeably faster than in-screen solutions, and I didn't have any issues with authentication. The side-mounted key doubles up as a multi-function button that lets you pull down the notification shade (a very nifty addition and one I used a lot), control media playback, launch Google Assistant, and so much more. As is often the case with ASUS, you get an extensive set of customization options for the button — you can set up slide, double press, and long press and hold actions for the key.

In a similar vein, ASUS also includes a double tap gesture at the back that can be used for toggling the flashlight on or off, launching Google Assistant or the camera, and controlling media playback. The side-mounted button and the back gesture go a long way in making the Zenfone 9 that much more convenient to use one-handed.

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

Oh, and there's a 3.5mm jack located at the top. It's incredulous to me that ASUS managed to fit the analog jack in this phone while Samsung didn't bother with it on the Galaxy S22 Ultra, a device that's 16.8mm taller and a full 9.8mm wider. Best of all, the Zenfone 9 gets IP68 dust and water resistance, making it immune to a dunk in the pool or the tub.

Overall, ASUS did a brilliant job with the design of the Zenfone 9. If you want a small Android phone that's great to hold and use and doesn't miss out on any of the extras that the best Android phones offer, this is the obvious choice.

ASUS Zenfone 9: Screen

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

The Zenfone 9 comes with a 5.9-inch Samsung AMOLED panel with an FHD+ (2400 x 1080) resolution, 120Hz refresh rate, and HDR10+. This is the same panel ASUS went with last year on the Zenfone 8, and you get a layer of Corning Gorilla Glass Victus. The screen goes up to a maximum of 800 nits in daily use and 1100 nits for HDR content, and I had zero issues with outdoor visibility.

This is the same Samsung 120Hz AMOLED panel as last year, and it continues to be terrific.

That said, there were a few scenarios where the ambient light sensor took a few seconds to adjust the screen's brightness. This is usually the case right after unlocking the screen, and I found that the brightness was set to a lower limit than what was needed for the ambient light. It's not anywhere as faulty as the Nothing phone (1), but I didn't notice this particular issue on the Zenfone 8, so it's worth mentioning. 

Other than that quibble, the screen is a delight to use. It has excellent colors and contrast levels, and like the Find X5 Pro, the panel is calibrated to a Delta-E<1 color accuracy at two brightness levels, giving you better colors with the brightness turned down. There's no dynamic refresh tech here, but you can choose between 60, 90, and 120Hz modes. There's a decent amount of customizability as well, including an always-on feature that's similar to what you get on the Pixels.

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

ASUS always does a great job optimizing its phones, and that's no different here. I switched to the Zenfone 9 after using the phone (1) and Pixel 6a, and it makes those devices feel slow. There's a level of immediacy with every interaction that you just don't get on other devices, even Samsung flagships — it reminds me of OnePlus in its heyday.

Another standout is the onboard audio. The stereo sound you get here is loud, detailed, and free of any distortion. ASUS once again went with Dirac for the tuning of the audio, and you get the brand's AudioWizard tuning engine that gives you a 10-band EQ and customized modes for gaming, movies, and day-to-day use. The 3.5mm jack uses Qualcomm's Aqstic WCD9385 DAC to deliver 32-bit 384kHz playback when using Hi-Res branded audio gear.

ASUS Zenfone 9: Performance

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

ASUS is in the first wave of manufacturers to release devices featuring Qualcomm's latest Snapdragon 8+ Gen 1 chipset, and that allows the Zenfone 9 to stand out just that bit more in the value flagship category. The Snapdragon 8+ Gen 1 is particularly interesting as it fixes one of the biggest issues with the Snapdragon 8 Gen 1: energy efficiency.

The Snapdragon 8+ Gen 1 delivers exciting gains over the standard Snapdragon 8 Gen 1.

The standard 8 Gen 1 is power hungry and devours batteries, and this is the case with all 2022 flagships that feature the platform. A big part of the issue has to do with Samsung LSI's 4nm node; it doesn't deliver any meaningful efficiency gains over the 5nm node, and with Qualcomm increasing the frequencies of its performance gains this generation, the 8 Gen 1 needs to throttle earlier to conserve power. 

Qualcomm mitigated the issue by switching to TSMC for the 8+ Gen 1; without going into the weeds too much, all I'll say is that TSMC's 4nm manufacturing node delivers much better efficiency.

The numbers speak for themselves: the Snapdragon 8+ Gen 1 delivers a noticeable 10% uptick in GPU and CPU performance, but it's the efficiency that turns it into a spectacular offering. For the same workloads, the 8+ Gen 1 consumes 30% less power than the 8 Gen 1, and that's an astounding figure when you consider Qualcomm didn't have to change the underlying architecture at all.

Anyway, what all of this means is that the Zenfone 9 delivers much better performance than just about any Android phone in the market today, and it does so while consuming less power. It's this efficiency that allowed ASUS to retain a small chassis while still delivering battery life in excess of a day.

To give you a car analogy, this is equivalent to Volkswagen putting a massive V12 engine in a Golf. Of course, the Golf cannot use anywhere close to the full potential of that V12 as it's front-wheel drive and will just spin the tires out. Thankfully, the Zenfone 9 is able to put that power down meaningfully. Here's a look at some synthetic scores:

Swipe to scroll horizontally
CategoryZenfone 9Galaxy S22 UltraiPhone 13
CrossMark (Overall) 10089991145
Productivity9679801135
Creativity10429901305
Responsiveness10361087795
Geekbench 5.1 (single-core)131110051717
Geekbench 5.1 (multi-core)428631524492
3DMark Wild Life (score)Maxed out69238647
3DMark Wild Life (FPS)Maxed out41.551.75
3DMark Wild Life Extreme (score)280120982418
3DMark Wild Life Extreme (FPS)16.7512.5514.45

As you can make out, the Snapdragon 8+ Gen 1 pulls into a significant lead in just about every category, and the fact that it does so while being more energy-efficient makes it the runaway leader on Android. That's evident when using the Zenfone 9; this is one of the fastest phones I used this year, and ASUS did a great job with the optimization — there's no lag or slowdowns anywhere in the interface.

ASUS Zenfone 9 review

(Image credit: Harish Jonnalagadda / Android Central)

The Zenfone 9 holds its own during gaming as well, delivering smooth framerates in visually demanding titles without breaking a sweat. I don't foresee this device slowing down for several years; as it is, the 8+ Gen 1 is overkill for most daily tasks and gaming. ASUS also added a large thermal cooling material at the back that makes a significant difference when gaming.

The device gets hot during extended gaming sessions, but it isn't the back where you'll feel the heat; the metal mid-frame gets hotter instead. The back of the phone got up to 39.2 degrees Celsius, and the sides were at 40.4 degrees — hot enough to be uncomfortable. This is with the High Performance mode activated; if you switch to the D