Phone Comparisons: ASUS ZenFone 8 vs Samsung Galaxy S21

AH ASUS ZenFone 8 vs Samsung Galaxy S21 comparison

This time around, we’re comparing the ASUS ZenFone 8 vs Samsung Galaxy S21. The ZenFone 8 is the newest flagship from ASUS, and a rather interesting phone. It launched quite recently, and what’s interesting is that it’s positioned above the ZenFone 8 Flip in the pecking order, it’s basically the company’s main flagship. Why is that weird? Well, the device is considerably smaller than most other major Android flagships. It’s not small, but it’s quite compact, which is something many people will appreciate.

Now, the moment this device launched, the Galaxy S21 came to mind. The ZenFone 8 is smaller than the Galaxy S21, but not by much. So, comparing these two phones does make sense, as they’re both flagship-grade smartphones. That’s exactly what we’ll do in this article, starting with their specifications. We’ll compare the two devices across a number of categories, including the design, display, performance, and more. Let’s kick off the ASUS ZenFone 8 vs Samsung Galaxy S21 comparison, shall we.


ASUS ZenFone 8Samsung Galaxy S21
Screen size5.9-inch fullHD+ Super AMOLED flat display (120Hz refresh rate)6.2-inch FullHD+ Dynamic AMOLED 2X display (120Hz adaptive refresh rate)
Screen resolution2400 x 10802400 x 1080
SoCQualcomm Snapdragon 888Qualcomm Snapdragon 888 or Samsung Exynos 2100
Storage128GB/256GB (UFS 3.1); non-expandable128GB/256GB, non-expandable
Rear cameras64MP (f/1.8 aperture, 0.8um pixel size, 26mm lens, PDAF, OIS)
12MP (ultra-wide, f/2.2 aperture, 112-degree FoV, 14mm lens, 1.4um pixel size, dual pixel PDAF)
12MP (f/1.8 aperture, 1.8um pixel size, OIS, Dual Pixel PDAF)
12MP (f/2.2 aperture, 1.4um pixel size, 120-degree FoV)
64MP (f/2.0 aperture, 0.8um pixel size, OIS, PDAF, Hybrid Optic 3X, 30X Space Zoom)
Front cameras12MP (f/2.5 aperture, 28mm lens, 1.22um pixel size, dual pixel PDAF)10MP (f/2.2 aperture, 1.22um pixel size, 80-degree FoV, Dual Pixel AF)
Battery4,000mAh, non-removable, 30W wired charging, reverse wired charging4,000mAh, non-removable, fast battery charging, Fast Wireless Charging 2.0, Wireless PowerShare
Dimensions148 x 68.5 x 8.9mm151.7 x 71.2 x 7.9mm
Weight169 grams169 grams
Connectivity5G, LTE, NFC, Bluetooth 5.2, Wi-Fi, USB Type-C5G, LTE, NFC, Bluetooth 5.2, Wi-Fi, USB Type-C
SecurityIn-display fingerprint scanner (optical)In-display fingerprint scanner (ultrasonic)
OSAndroid 11
ZenUI 8
Android 11
One UI 3.0
Price€599 / €669 / €799$799.99

ASUS ZenFone 8 vs Samsung Galaxy S21: Design

When it comes to the design, the two phones do look different. They both come with a frame made out of metal, but their backplates are different. The ZenFone 8 includes glass on its back, while the Galaxy S21 utilizes plastic. Both of them have thin bezels, and a display camera hole. The position of the display camera hole is different in comparison. On the ZenFone 8 it sits in the top-left corner, while it is centered on the Galaxy S21.


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You’ll notice that their back sides look different as well. The ZenFone 8 has a more regular-looking camera island towards the top-left corner. The Galaxy S21’s camera island is an extension of its frame, and it’s positioned in the top-left corner. Branding orientations are different on the back, while both phones feature physical buttons on the right side. The power / lock button is placed below the volume up / down buttons on both devices.

The two phones do have a similar in-hand feel, despite the fact the Galaxy S21 has a plastic backplate. They are completely equal when it comes to heft, they weigh 169 grams. The ZenFone 8 is a bit shorter, and noticeably narrower. It is thicker, however, by 1mm. Both devices do feel more than premium in the hand. They are quite compact, while they managed to retain really respectable display sizes. If you’re not a fan of gigantic phones, these two may appeal to you.


ASUS ZenFone 8 vs Samsung Galaxy S21: Display

The ASUS ZenFone 8 features a 5.9-inch fullHD+ (2400 x 1080) Super AMOLED display. That panel offers a 120Hz refresh rate, and it’s an LTPS panel, it doesn’t offer an adaptive refresh rate. It does support HDR10+ content, and it has a peak brightness of 1,100 nits. The display is protected by the Gorilla Glass Victus, and it’s flat. The Galaxy S21’s display is a bit different in comparison.

The Galaxy S21 sports a 6.2-inch fullHD+ (2400 x 1080) Dynamic AMOLED 2X display. This display also offers a 120Hz refresh rate, but it’s an LTPO panel. In other words, it offers an adaptive refresh rate. It offers the same aspect ratio, and it does support HDR10+ content, just like the ZenFone 8’s offering. This display is protected by the Gorilla Glass Victus as well, and it’s also flat. It gets quite bright at 1,300 nits peak brightness.

So, on paper, the Galaxy S21 does offer a more modern display. The fact that it’s an LTPO panel is enough to make that distinction. What about in practice? Well, both of these displays are excellent. They’re more than sharp enough, with great viewing angles, and very vivid colors. Both displays also get more than bright enough, not to mention that they’re both also quite fluid, which is especially noticeable while scrolling. You cannot go wrong with either one, based on what their displays offer.


ASUS ZenFone 8 vs Samsung Galaxy S21: Performance

The performance is second to none on both phones, which is to be expected. Both of these phones are fueled by the Snapdragon 888 SoC, though the Galaxy S21 also comes in the Exynos 2100 variant (Europe and India). On top of that, both phones offer really fast RAM, and UFS 3.1 flash storage on top of that. They both ship with Android 11, though their skins are considerably different in comparison. ASUS tries to stick to stock Android as much as possible.

The scrolling is extremely fluid on both phones, thanks to their refresh rates. Both companies did a really good job at adapting their software to the display and the rest of the hardware. They can open and close apps extremely fast, while multitasking, in general, is quite enjoyable. We didn’t notice any browsing issues, or anything of the sort, while they do a good job when it comes to operating cameras, and so on. Day-to-day usage is excellent in pretty much every regard.

Some of you are probably wondering about gaming. Well, you’ll be glad to hear that both phones can run pretty much any game in the Play Store, and do it in style. The ZenFone 8 does have more gaming features, though, as ASUS took quite a few of them from the ROG Phone, and placed it inside this device. Both phones get warm during gaming, but that shouldn’t concern you.


ASUS ZenFone 8 vs Samsung Galaxy S21: Battery

The ZenFone 8 utilizes a 4,000mAh battery, and the same goes for the Galaxy S21. Samsung’s flagship does have a larger display to juice up, though, but it also has a more advanced display tech. You’re probably wondering if the battery life is any good on the two phones? Well, yes, it is, it’s not great, though. These two phones will offer more than enough juice for the vast majority of consumers, though.

So, if you’re not a gamer, and you don’t run many processor-intensive tasks during the day, both phones can reach 6 hours of screen-on-time. Realistically, for us, that number was usually between 5 and 6 hours, though, even without gaming. That will be plenty for most people, but if you’re a power user, you may end up being disappointed. It all depends on how much you tend to use your phone, and if you run processor-intensive games on it.

If you do run out of juice ahead of time, you’ll be glad to know that both phones support fast charging. The ASUS ZenFone 8 supports 30W fast wired charging, while it also has support for reverse wired charging. The Galaxy S21 supports 25W fast wired charging, along with 15W wireless charging, and also reverse wireless charging. ASUS’ phone does support faster charging overall, but it doesn’t offer wireless charging at all, unlike the Galaxy S21.


ASUS ZenFone 8 vs Samsung Galaxy S21: Cameras

First and foremost, let’s just say that both of these phones offer really good camera setups. The ZenFone 8 is a major improvement in comparison with its predecessor, it’s not even close. The phone delivers a lot better dynamic range, far more vivid colors, sharper photos, and even much better low light performance. The Galaxy S21 is really good in all those regards as well, though the two phones do deliver somewhat different results.

Samsung Galaxy S21 Review AM AH 09

The ZenFone 8 has a 64-megapixel main camera (the same as its predecessor), and a 12-megapixel ultra-wide unit on the back. The Galaxy S21 has two 12-megapixel cameras on the back (wide and ultra-wide), in addition to a 64-megapixel telephoto unit. Images from the main cameras on these two phones, during the day, are excellent. You’ll get a great dynamic range, vivid colors, and really sharp pictures. The Galaxy S21 tends to saturate pictures a bit more, though, which is something that most people seem to prefer.


Ultra-wide cameras are really good on both phones, and don’t stray too much away from the main cameras in terms of quality. They’re not as good, but they’re not that far either. In low light, both phones do more than a respectable job. Both can light up an image quite a bit thanks to built-in photography modes for dark environments. They balance out images really well, and even manage to attain quite a bit of detail from the shadows. The noise is well-controlled by both phones. If you prefer more saturated images, the Galaxy S21 is the way to go. If you want more true-to-life ones, the ZenFone 8 is an excellent choice. Both offer flagship-grade cameras.


In regards to audio, well, both phones have a lot to offer. The ZenFone 8 speaker quality managed to surprise us quite a bit, especially considering the size of the device. ASUS managed to include truly nice speakers inside of the device. The Galaxy S21 has really good stereo speakers, as we already knew, so… you can’t go wrong with either device, to be quite honest.

Both phones offer stereo speaker setups. The Galaxy S21’s setup is a bit louder, while the ZenFone 8’s setup is a bit sharper. The difference is minimal, though, and they’re both excellent in that regard, better than most of the competition. The ZenFone 8 even has a 3.5mm headphone jack, in case you need it. If you hook up a pair of headphones on either phone, you’ll get well-balanced audio. We really don’t have any audio-related complaints.