Asus Zenfone 9 review: The iPhone mini alternative for

Pros

  • Compact size is refreshing to use
  • Uncompromising build quality and performance
  • Simple and bloatware-free software
  • Essentials like the 3.5mm headphone jack and charger are included

Cons

  • Speakers come off as tinny
  • Adaptive refresh rate is overly aggressive
  • Lackluster video recording
  • Only 2 years of OS updates

When you market a device as having flagship features in a compact size, there are big expectations. While they were once a familiar form factor, small-sized phones have since been overshadowed by “Ultra” and “Pro” handsets, with displays that span from 6.5 inches and beyond. (Let’s not even talk about the tablet-aspiring foldables.)

We’ve seen this story before: Manufacturers try to satisfy a niche customer segment by being different, unique, and just bold enough to capture some nostalgia points along the way. In the end, the demand just isn’t there. Why settle for a smaller, short-handed phone when you can just buy a larger, safer, and uncompromised Goliath?

Asus is doing something different with the new Zenfone 9. In this story, David is equipped with high-end specifications and features, with drawbacks that are less apparent than other compact phones — including Apple’s. After two weeks of testing the handset, here are my pluses and minuses to help you decide whether the Zenfone is right for you.

Specifications

Processor Qualcomm Snapdragon 8+ Gen 1
Display 5.9-inch AMOLED, 2400×1080 pixels, 120Hz refresh rate  
Weight 169g (5.96oz)

RAM/Storage

8GB/128GB, 8GB/256GB, 16GB/256GB

Cameras

50MP main camera with 6-Axis Hybrid Gimbal OIS, 12MP ultra-wide (113-degree FOV), and 12MP front camera

Battery 4,300mAh with 30W fast charging  
Connectivity 3.5mm headphone jack, USB-C, Bluetooth 5.2, Wi-Fi 802.11ac  

Operating system

Zen UI based on Android 12

Colors

Midnight Black, Moonlight White, Starry Blue, Sunset Red

Price Starting at $699


Design

Without question, the standout feature of the Asus Zenfone 9 is its size. The display measures at 5.9 inches, which puts it well below average in terms of 2022 flagships. Still, adapting to the smaller figure is much easier than you’d expect. For one, Asus shaped the Zenfone in a 20:9 aspect ratio, meaning it stands taller and more narrow compared to traditional 18.5:9 devices (i.e iPhones, Samsung Galaxies, etc.). Secondly, the AMOLED panel supports FHD resolution (2,400 by 1,080 pixels) and a 120Hz refresh rate, making the transition from other high-end phones very seamless. 

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The 5.9-inch Zenfone 9 gets towered by today’s flagships.

June Wan/ZDNet

In the hand, the Zenfone 9 greets you with its soft-touch, rubberized back cover. It’s non-removable, which I was bummed to find out about after seeing all the fun and poppy colors that Asus offered the phone in, but does a surprisingly adequate job of resisting any fingerprints and smudges. The added grip from the textured backing is easy to appreciate, and it’s chased by the smooth-feeling aluminum railing that surrounds the device. 

Along the edge is a power button that — get this — triples as a fingerprint scanner and slider key. Here’s what I have to say about the two: they’re almost too reliable. In many cases when I just want to see my notifications from the lock screen, even the slightest tap on the power button unlocks the phone, bypassing the lock screen instead of just waking it. There’s no “Double tap to wake” feature on the Zenfone, either. 

As for the slider key, it’s very useful for scrolling through webpages and pulling down the notification panel but, again, is very sensitive. I often found myself unintentionally navigating through apps because of how I was holding the phone. You can, of course, turn off the slider key (which Asus calls “Smart key”) feature in the settings. 

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Midnight Black wouldn’t be my first choice but it looks sleek and feels great in the hand. 

June Wan/ZDNet

Still, I found the sensitivity issues easy to dismiss because the rest of the Zenfone is undeniably pleasant. Considering the stylistic design, dual speakers, and 3.5mm headphone jack, Asus managed to get the device certified for IP68 water and dust resistance, which is reassuring for folks who are buying the phone under warranty. I also had no problem receiving 4G LTE and hints of 5G connections on my T-Mobile sim. Your mileage may vary. 

With compact phones, we typically see manufacturers slim down battery sizes to accommodate the smaller figure. Not here. Instead, Asus made the Zenfone 9 thicker than its predecessor, slotting a healthy 4,300mAh battery under the hood. More on battery life later.  

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The Zenfone 9 measures at 9.1mm thick. That’s before you snap on a case.

June Wan/ZDNet

Software

The Zenfone 9 operates on Asus’ Zen UI software, layered over Android 12. It’s simplistic, clean, bloatware-free (save for the Asus Data Transfer app), and should appeal to stock Android enthusiasts. Naturally, the brand’s taken some key elements from Google’s Pixel Launcher like the enlarged clock in the always-on display, Material You theming, and bubbly notification toggles. Coming from a gaming phone that I’ve been testing alongside the Asus, I appreciate the minimalist approach to Zen UI. 

Also: Best smartphones to buy in 2022

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Zen UI is clean, user-friendly, and just as customizable.   

Screenshot: June Wan/ZDNet

My main gripe with Asus’ software is its longevity. Right now, the company is only committing to two years of operating system (OS) updates, which means the Zenfone 9 will end its software support after Android 14. While that won’t come until 2024, if you’re expecting to use the phone for more than two years — which many of you likely are — then the short-term commitment by Asus should be one of your main concerns. 

Does that mean you can no longer use the phone after 2024? No. But the lack of OS and security updates can (and will) make your device more vulnerable to viruses and attacks.

Also: Comparing software upgrade policies from Samsung, Apple, and Google

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June Wan/ZDNet

Performance

Future talk aside, my experience using the Asus Zenfone 9 has been lovely. As I noted with the display, switching over to the Asus was seamless and didn’t require much adjustment. That meant that my typical routine of web browsing, streaming shows and movies, taking pictures, and doing general phone things was unchanged. 

The Zenfone 9, much like its gaming sibling, is powered by the latest Qualcomm Snapdragon 8+ Gen 1 chipset, which allows it to power through most apps, games, and services you throw at it. While I’d advise mobile gamers to look at larger-screen, larger battery devices, the Zenfone 9 is still plenty capable for play. There were moments when the phone felt warm when running Genshin Impact and Minecraft, but it never got to the point where I needed to set it down to chill out. For a compact phone with 8GB of RAM and not much interior space to cool itself, I was impressed. 

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Viewing angles are great, too.

June Wan/ZDNet

Audio quality on the Asus is just okay. I found the dual stereo speakers’ output tinny and lacking in bass, which, for watching movies and gaming, made the experiences less than desirable. The speaker system also doesn’t get as loud as I’d hoped. As someone who likes to play music while cooking, I was left with hearing my pan sizzle more than anything else. 

Lastly, it’s worth noting that Asus gives you four refresh rate options with the Zenfone 9: 120Hz, 90Hz, 60Hz, and Auto. I’m a big fan of manufacturers who let you dial down to 90Hz and not just jump from 120Hz to 60Hz, so that’s a plus. However, the Zenfone 9’s refresh rate is noticeably aggressive in Auto mode. Depending on what app you’re using, the phone switches between the three values so quickly that it gives off the impression of stuttering. For me, leaving the display at 120Hz made for the smoothest user experience. 

Also: Hands-on with the Asus ROG Phone 6 and 6 Pro

Camera

The Zenfone 9 isn’t the most expensive phone by any means — it starts at $699 — so I was delighted to see that Asus went with only two cameras and nothing more. (We often see phone-makers put extra, low-quality cameras to satisfy the “quad-camera” marketing jargon.) 

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The two camera lenses are large but identical in size

June Wan/ZDNet

By putting more effort into the 50MP main lens and 12MP ultra-wide, pictures captured with the Zenfone are full of vibrancy and sharpness. Check out the sample below, which was captured by the ultra-wide lens. While sunny, the camera was able to keep the Brooklyn bridge in focus, while balancing the tones and colors of the sky — and the buildings across the river. 

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An afternoon drive by the Brooklyn Bridge. Captured with the ultra-wide lens.

June Wan/ZDNet

I’m a little more on the fence when it comes to video recording with the Zenfone 9. Asus is touting a new 6-Axis Hybrid Gimbal OIS Stabilizer that makes footage appear more steady, shake-free, and fluid. While that’s certainly been the case when recording with movement (see video below), the camera appears to have problems balancing its exposure, with gradual shifts between darker and lighter tones. There’s also a noticeable lack of detail, albeit the HyperSteady feature limits you to 1080p video. 

Battery

Going into this review, I was skeptical about the Zenfone 9’s battery life. My past experiences with the iPhone SE (2020) and iPhone 13 mini had conditioned me to associate subpar endurance with smaller phones. You simply can’t fit in the same battery capacity as the larger alternatives. 

But by making the Zenfone 9 thicker, Asus has proven that a small shift in design is all it takes. The Zenfone’s 4,300mAh cell has lasted me an average of five and a half screen-on-time (SOT) per day, hovering around the 12% mark at the end of every night. 

To charge, Asus includes a 30-watt, USB-C charger in the box that can top up the Zenfone within an hour’s time. There’s no wireless charging on the device, though. 

Bottom line

Asus has done it again. The $699 Zenfone 9 is a small phone that delivers big performance. By making clever sacrifices (if you perceive a thicker phone as one), the latest flagship carries similar processing power, battery life, and software features as its larger counterparts. 

What should you watch out for? The underwhelming software update policy, average video recording and audio output, and over-aggressive variable refresh rate are my main call-outs. Here’s the thing: besides the tinny speakers, all of those issues can still be solved via future updates. For now, it’s just a matter of consumers showing the demand and Asus following up on it. 

Alternatives to consider

Besides the ASUS Zenfone 9, here are three worthy alternatives that you should consider:

Due to its wider dimensions, the Samsung Galaxy S22 is around the same size as the Asus Zenfone 9, even though it has a larger 6.1-inch display. The phone doesn’t have the same Qualcomm processor, but the Snapdragon 8 Gen 1 is still a formidable chipset and the S22’s camera system is arguably better than Asus’. You can also expect up to four years of OS updates with Samsung.

For small phone enthusiasts, the Apple iPhone 13 mini should be at the top of your bucket list. It’s the most compact iPhone that’s powered by Apple’s latest chipset and fields a reliable, dual-camera setup for photo and video capture. Battery life takes a hit, but the security and longevity of iOS-powered devices may be worth the pick-up. 

Technically a compact phone when it’s closed shut, the Samsung Galaxy Z Flip 3 brings back the old clamshell phone days with a foldable AMOLED display, 5G support, and all the software perks of One UI. The phone is easy to pocket, has a durable hinge, and is rated IPX8 for water resistance.