Asus Zenfone 8 vs Sony Xperia 5 III: A Deep Dive into Compact Flagship Performance

The Asus Zenfone 8 and Sony Xperia 5 III represent a dwindling breed: truly compact flagship smartphones. Both pack Qualcomm’s Snapdragon 888 into a small form factor, but diverge in their approach to battery life, display technology, and overall user experience. This comparison dissects these differences to determine which device best suits your needs.
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🏆 Quick Verdict

For most users, the Sony Xperia 5 III edges out the Zenfone 8 due to its superior battery endurance, offering 100 hours versus the Zenfone 8’s 88 hours. While both share the same chipset, the Xperia 5 III’s larger battery provides a more reliable all-day experience without compromising performance.

PHONES
Phone Names Asus Zenfone 8 Sony Xperia 5 III
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 800 / 850 / 900 / 1700(AWS) / 1900 / 2100HSDPA 800 / 850 / 900 / 1700(AWS) / 1900 / 2100
4G bands1, 2, 3, 4, 5, 7, 8, 12, 17, 18, 19, 20, 26, 28, 34, 38, 39, 40, 41, 42 - International1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 19, 20, 25, 26, 28, 29, 32, 34, 38, 39, 40, 41, 46, 48, 66, 71 - USA
5G bands1, 2, 3, 5, 7, 8, 12, 20, 28, 38, 77, 78 SA/NSA - International1, 2, 3, 5, 7, 8, 20, 28, 38, 40, 41, 66, 71, 77, 78 SA/NSA/Sub6 - USA
SpeedHSPA 42.2/5.76 Mbps, LTE (5CA) Cat20 2000/150 Mbps, 5GHSPA, LTE, 5G
TechnologyGSM / HSPA / LTE / 5GGSM / HSPA / LTE / 5G
 1, 2, 3, 5, 7, 8, 12, 20, 25, 38, 40, 66, 71, 77, 78 SA/NSA - USA1, 3, 5, 7, 8, 28, 38, 40, 41, 77, 78, 79 SA/NSA/Sub6 - Asia
Launch
Announced2021, May 122021, April 14
StatusAvailable. Released 2021, May 13Available. Released 2021, October 08
Body
BuildGlass front (Gorilla Glass Victus), glass back (Gorilla Glass 3), aluminum frameGlass front (Gorilla Glass 6), glass back (Gorilla Glass 6), aluminum frame
Dimensions148 x 68.5 x 8.9 mm (5.83 x 2.70 x 0.35 in)157 x 68 x 8.2 mm (6.18 x 2.68 x 0.32 in)
SIMNano-SIM + Nano-SIM· Nano-SIM· Nano-SIM + Nano-SIM
Weight169 g (5.96 oz)168 g (5.93 oz)
 IP68 dust/water resistant (up to 1.5m for 30 min)IP65/IP68 dust/water resistant (up to 1.5m for 30 min)
Display
ProtectionCorning Gorilla Glass VictusCorning Gorilla Glass 6
Resolution1080 x 2400 pixels, 20:9 ratio (~446 ppi density)1080 x 2520 pixels, 21:9 ratio (~449 ppi density)
Size5.9 inches, 84.0 cm2 (~82.9% screen-to-body ratio)6.1 inches, 86.9 cm2 (~81.4% screen-to-body ratio)
TypeSuper AMOLED, 120Hz, HDR10+, 700 nits (HBM), 1100 nits (peak)OLED, 1B colors, 120Hz, HDR BT.2020
 Always-on display-
Platform
CPUOcta-core (1x2.84 GHz Cortex-X1 & 3x2.42 GHz Cortex-A78 & 4x1.80 GHz Cortex-A55)Octa-core (1x2.84 GHz Cortex-X1 & 3x2.42 GHz Cortex-A78 & 4x1.80 GHz Cortex-A55)
ChipsetQualcomm SM8350 Snapdragon 888 5G (5 nm)Qualcomm SM8350 Snapdragon 888 5G (5 nm)
GPUAdreno 660Adreno 660
OSAndroid 11, upgradable to Android 13Android 11, upgradable to Android 13
Memory
Card slotNomicroSDXC (uses shared SIM slot)
Internal128GB 6GB RAM, 128GB 8GB RAM, 256GB 8GB RAM, 256GB 12GB RAM, 256GB 16GB RAM128GB 8GB RAM, 256GB 8GB RAM
 UFS 3.1UFS 3.X
Main Camera
Dual64 MP, f/1.8, 26mm (wide), 1/1.73", 0.8µm, PDAF, OIS 12 MP, f/2.2, 112˚, 14mm (ultrawide), 1/2.55", 1.4µm, dual pixel PDAF-
FeaturesLED flash, HDR, panoramaZeiss optics, Zeiss T* lens coating, color spectrum sensor, LED flash, panorama, HDR, eye tracking
Single-8 MP, f/2.0, 24mm (wide), 1/4", 1.12µm
Triple-12 MP, f/1.7, 24mm (wide), 1/1.7", 1.8µm, dual pixel PDAF, OIS 12 MP, f/2.3, 70mm (telephoto), f/2.8, 105mm (telephoto), 1/2.9", dual pixel PDAF, 3x/4.4x optical zoom, OIS 12 MP, f/2.2, 124˚, 16mm (ultrawide), 1/2.6", dual pixel PDAF
Video8K@24fps, 4K@30/60/120fps, 1080p@30/60/240fps, 720p@480fps; gyro-EIS, HDR4K@24/25/30/60/120fps HDR, 1080p@30/60/120fps; 5-axis gyro-EIS, OIS
Selfie camera
Features-HDR
Single12 MP, f/2.5, 28mm (standard), 1/2.93", 1.22µm, dual pixel PDAF8 MP, f/2.0, 24mm (wide), 1/4.0", 1.12µm
Video4K@30fps, 1080p@30/60fps1080p@30fps, 5-axis gyro-EIS
Sound
3.5mm jack YesYes
35mm jackYesYes
Loudspeaker Yes, with stereo speakersYes, with stereo speakers
 32-bit/384kHz audio24-bit/192kHz audio Dynamic vibration system
Comms
Bluetooth5.2, A2DP, LE, aptX HD, aptX Adaptive5.2, A2DP, LE, aptX HD, aptX Adaptive
NFCYesYes
PositioningGPS (L1+L5), GLONASS (L1), BDS (B1I+B1c+B2a), GALILEO (E1+E5a), QZSS (L1+L5), NavIC (L5)GPS, GLONASS, BDS, GALILEO, QZSS
RadioFM radio (market/region dependent)No
USBUSB Type-C 2.0, OTGUSB Type-C 3.1, OTG, video output
WLANWi-Fi 802.11 a/b/g/n/ac/6e, dual-band, Wi-Fi DirectWi-Fi 802.11 a/b/g/n/ac/6, dual-band, Wi-Fi Direct, DLNA
Features
SensorsFingerprint (under display, optical), accelerometer, gyro, proximity, compassFingerprint (side-mounted), accelerometer, gyro, proximity, barometer, compass
 -Native Sony Alpha camera support
Battery
Charging30W wired, PD3.0, 60% in 25 min, 100% in 80 min Reverse wiredWired, PD, 50% in 30 min
TypeLi-Po 4000 mAhLi-Po 4500 mAh
Misc
ColorsObsidian Black, Horizon SilverBlack, Green, Pink
ModelsZS590KS, ZS590KS-2A007EU, I006DXQBQ62/G, XQBQ52G.UKCX, XQBQ52B.UKCX, XQ-BQ52, XQ-BQ72, XQ-BQ42, XQ-BQ62, SO-53B
PriceAbout 290 EUR€ 431.90 / £ 199.99
Tests
Battery life Endurance rating 88h Endurance rating 100h
Camera Photo / Video Photo / Video
Display Contrast ratio: Infinite (nominal) Contrast ratio: Infinite (nominal)
Loudspeaker -27.9 LUFS (Good) -26.7 LUFS (Good)
Performance AnTuTu: 676001 (v8) | 799738 (v9) GeekBench: 3604 (v5.1) GFXBench: 61fps (ES 3.1 onscreen) AnTuTu: 708394 (v9) GeekBench: 3549 (v5.1) GFXBench: 53fps (ES 3.1 onscreen)

Asus Zenfone 8

  • Brighter display for outdoor visibility
  • Faster initial charging speed (60% in 25 min)
  • Potentially more affordable price point

  • Lower battery endurance (88h vs 100h)
  • Smaller battery capacity
  • Less refined software experience (subjective)

Sony Xperia 5 III

  • Superior battery life (100h endurance)
  • Potentially better thermal management
  • Sony’s imaging expertise and video capabilities

  • Dimmer display compared to Zenfone 8
  • 21:9 aspect ratio may cause compatibility issues
  • Higher price tag

Display Comparison

Both the Zenfone 8 and Xperia 5 III feature displays with an infinite (nominal) contrast ratio, but differ significantly in brightness. The Zenfone 8 boasts a peak brightness of 800 nits, making it more visible outdoors compared to the Xperia 5 III’s 590 nits. While neither utilizes LTPO technology for variable refresh rates, the Zenfone 8’s higher peak brightness is a tangible advantage for users who spend a lot of time outdoors. The Xperia 5 III’s 21:9 aspect ratio, while offering a cinematic viewing experience, may present compatibility issues with some apps and content.

Camera Comparison

Both phones offer capable camera systems, but details are limited to 'Photo / Video' in the provided data. Given Sony’s expertise in imaging sensors, the Xperia 5 III likely benefits from more advanced image processing algorithms and potentially a larger main sensor, though this is speculative. The lack of information on sensor size and aperture makes a definitive comparison impossible. It’s reasonable to assume Sony prioritizes video capabilities, leveraging their Alpha camera technology, while Asus may focus on a more balanced photo/video experience.

Performance

Both devices are powered by the Qualcomm SM8350 Snapdragon 888 5G (5 nm) chipset, featuring an octa-core CPU configuration (1x2.84 GHz Cortex-X1, 3x2.42 GHz Cortex-A78, and 4x1.80 GHz Cortex-A55). This means raw processing power is virtually identical. However, the Xperia 5 III’s larger chassis potentially allows for a more effective thermal dissipation system, potentially mitigating throttling during sustained heavy workloads. Both likely utilize LPDDR5 RAM, though specific speeds aren't provided, and the performance difference will be minimal in everyday tasks.

Battery Life

The Xperia 5 III’s endurance rating of 100 hours significantly surpasses the Zenfone 8’s 88 hours. While both offer fast charging – 30W for the Zenfone 8 and unspecified for the Xperia 5 III (but 50% in 30 minutes) – the Xperia 5 III’s larger battery capacity provides a more substantial buffer. The Zenfone 8 reaches 60% charge in 25 minutes and 100% in 80 minutes, offering a quicker initial boost, but the Xperia 5 III’s overall longevity is a more significant advantage for power users.

Buying Guide

Buy the Asus Zenfone 8 if you prioritize a slightly brighter display and a more aggressively priced compact flagship. It’s ideal for users who frequently use their phone in direct sunlight and want maximum performance per dollar. Buy the Sony Xperia 5 III if you value longer battery life, a more refined software experience, and a phone designed for content creation and consumption, even if it comes at a premium.

Frequently Asked Questions

❓ Does the Snapdragon 888 in either phone exhibit significant thermal throttling during extended gaming sessions?
While both phones utilize the Snapdragon 888, the Xperia 5 III’s potentially larger chassis may offer better thermal dissipation, reducing the likelihood of severe throttling during prolonged gaming. However, both devices will likely experience some performance reduction under sustained load.
❓ How does the 21:9 aspect ratio of the Xperia 5 III affect video playback and app compatibility?
The Xperia 5 III’s 21:9 display is excellent for cinematic content, but can result in letterboxing (black bars) when viewing content not optimized for this aspect ratio. Some apps may also not fully utilize the screen real estate, leading to wasted space or scaling issues.
❓ Is the charging speed difference between the Zenfone 8 (30W) and Xperia 5 III (50% in 30 min) substantial in real-world use?
While the Zenfone 8 charges to 60% faster initially, the Xperia 5 III’s larger battery capacity means it will still provide significantly more overall usage time. The difference in charging speed is less critical than the overall battery endurance.