Samsung Galaxy S25 vs. Asus Zenfone 12 Ultra: Which Flagship Reigns Supreme?

The Samsung Galaxy S25 represents the latest iteration of Samsung’s flagship, while the Asus Zenfone 12 Ultra aims to disrupt the market with a focus on longevity and rapid charging. Both devices leverage the Qualcomm Snapdragon 8 Elite, but diverge significantly in battery performance and display technology, creating a compelling head-to-head for power users and everyday consumers alike.
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🏆 Quick Verdict

For the average user prioritizing all-day battery life and incredibly fast charging, the Asus Zenfone 12 Ultra is the clear winner. Its 61-hour endurance and 65W charging significantly outperform the S25. However, the S25’s brighter display and established ecosystem may appeal to Samsung loyalists.

PHONES
Phone Names Samsung Galaxy S25 Asus Zenfone 12 Ultra
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 850 / 900 / 1700(AWS) / 1900 / 2100HSDPA 800 / 850 / 900 / 1700(AWS) / 1900 / 2100
4G bands1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28, 32, 38, 39, 40, 41, 66 - International1, 2, 3, 4, 5, 7, 8, 12, 17, 18, 19, 20, 25, 26, 28, 32, 34, 38, 39, 40, 41, 42, 43, 48, 66
5G bands1, 2, 3, 5, 7, 8, 12, 20, 25, 26, 28, 38, 40, 41, 66, 75, 77, 78 SA/NSA/Sub6 - International1, 2, 3, 5, 7, 8, 12, 18, 20, 25, 26, 28, 38, 40, 41, 48, 66, 77, 78, 79 SA/NSA
SpeedHSPA, LTE (up to 7CA), 5GHSPA, LTE, 5G
TechnologyGSM / CDMA / HSPA / EVDO / LTE / 5GGSM / HSPA / LTE / 5G
Launch
Announced2025, January 222025, February 06
StatusAvailable. Released 2025, February 03Available. Released 2025, February 28
Body
BuildGlass front (Gorilla Glass Victus 2), glass back (Gorilla Glass Victus 2), aluminum frameGlass front (Gorilla Glass Victus 2), aluminum frame, glass back
Dimensions146.9 x 70.5 x 7.2 mm (5.78 x 2.78 x 0.28 in)163.8 x 77 x 8.9 mm (6.45 x 3.03 x 0.35 in)
SIM· Nano-SIM + Nano-SIM + eSIM + eSIM (max 2 at a time) - INT· Nano-SIM + eSIM + eSIM (max 2 at a time) - USA· Nano-SIM + Nano-SIM - CNNano-SIM + Nano-SIM + eSIM (max 2 at a time)
Weight162 g (5.71 oz)220 g (7.76 oz)
Display
ProtectionCorning Gorilla Glass Victus 2, Mohs level 5Corning Gorilla Glass Victus 2, Mohs level 6
Resolution1080 x 2340 pixels, 19.5:9 ratio (~416 ppi density)1080 x 2400 pixels, 20:9 ratio (~388 ppi density)
Size6.2 inches, 94.4 cm2 (~91.1% screen-to-body ratio)6.78 inches, 111.0 cm2 (~88.0% screen-to-body ratio)
TypeDynamic LTPO AMOLED 2X, 120Hz, HDR10+, 2600 nits (peak)LTPO AMOLED, 144Hz, HDR10, 1600 nits (HBM), 2500 nits (peak)
Platform
CPUOcta-core (2x4.47 GHz Oryon V2 Phoenix L + 6x3.53 GHz Oryon V2 Phoenix M)Octa-core (2x4.32 GHz Oryon V2 Phoenix L + 6x3.53 GHz Oryon V2 Phoenix M)
ChipsetQualcomm SM8750-AC Snapdragon 8 Elite (3 nm)Qualcomm SM8750-AB Snapdragon 8 Elite (3 nm)
GPUAdreno 830 (1200 MHz)Adreno 830
OSAndroid 15, up to 7 major Android upgrades, One UI 7Android 15, upgradable to Android 16, up to 2 major Android upgrades
Memory
Card slotNoNo
Internal128GB 12GB RAM, 256GB 12GB RAM, 512GB 12GB RAM256GB 12GB RAM, 512GB 16GB RAM
Main Camera
FeaturesBest Face, LED flash, auto-HDR, panoramaLED flash, HDR, panorama
Triple50 MP, f/1.8, 24mm (wide), 1/1.56", 1.0µm, dual pixel PDAF, OIS 10 MP, f/2.4, 67mm (telephoto), 1/3.94", 1.0µm, PDAF, OIS, 3x optical zoom 12 MP, f/2.2, 13mm, 120˚ (ultrawide), 1/2.55" 1.4µm, Super Steady video50 MP, f/1.9, 24mm (wide), 1/1.56", 1.0µm, PDAF, gimbal OIS 32 MP, f/2.4, 65mm (telephoto), 1/3.2", 0.7µm, PDAF, OIS, 3x optical zoom 13 MP, f/2.2, 13mm, 120˚ (ultrawide), 1/3.0", 1.12µm
Video8K@24/30fps, 4K@30/60fps, 1080p@30/60/120/240fps, 10-bit HDR, HDR10+, stereo sound rec., gyro-EIS8K@24fps, 4K@30/60fps, 1080p@30/60/120/240fps, 720p@480fps; gyro-EIS, HDR10+
Selfie camera
FeaturesHDR, HDR10+Panorama, HDR
Single12 MP, f/2.2, 26mm (wide), 1/3.2", 1.12µm, dual pixel PDAF32 MP, f/2.5, 22mm (wide), 1/3.2", 0.7µm
Video4K@30/60fps, 1080p@30fps1080p@30fps
Sound
35mm jackNoYes
Loudspeaker Yes, with stereo speakersYes, with stereo speakers
Comms
Bluetooth5.4, A2DP, LE5.4, A2DP, LE, aptX HD, aptX Adaptive, aptX Lossless
NFCYesYes
PositioningGPS, GLONASS, BDS, GALILEO, QZSSGPS (L1+L5), BDS (B1I+B1c+B2a), GALILEO (E1+E5a), QZSS (L1+L5), NavIC, GLONASS
RadioNoNo
USBUSB Type-C 3.2, DisplayPort 1.2, OTGUSB Type-C
WLANWi-Fi 802.11 a/b/g/n/ac/6e/7, tri-band, Wi-Fi DirectWi-Fi 802.11 a/b/g/n/ac/6e/7, tri-band, Wi-Fi Direct
Features
SensorsFingerprint (under display, ultrasonic), accelerometer, gyro, proximity, compass, barometerFingerprint (under display, optical), accelerometer, gyro, proximity, compass
Battery
Charging25W wired, PD3.0, 50% in 30 min 15W wireless (Qi2 Ready) 4.5W reverse wireless65W wired, PD3.0, PPS, QC5, 100% in 39 min 15W wireless (Qi) 10W reverse wired
TypeLi-Ion 4000 mAh5500 mAh
Misc
ColorsIcy Blue, Mint, Navy, Silver Shadow, Pink Gold, Coral Red, Blue BlackEbony Black, Sakura White, Sage Green
ModelsSM-S931B, SM-S931B/DS, SM-S931U, SM-S931U1, SM-S931W, SM-S931N, SM-S9310, SM-S931E, SM-S931E/DSAI2501, AI2501H, I2501C, AI2501B
Price$ 674.99 / C$ 689.00 / £ 435.99 / € 548.13 / ₹ 80,999€ 955.55
SAR1.13 W/kg (head)     0.92 W/kg (body)-
SAR EU1.29 W/kg (head)     1.36 W/kg (body)-
EU LABEL
Battery37:16h endurance, 2000 cycles61:00h endurance, 1200 cycles
EnergyClass BClass A
Free fallClass A (270 falls)Class D (45 falls)
RepairabilityClass CClass C

Samsung Galaxy S25

  • Brighter display for outdoor visibility.
  • Potentially slightly faster CPU performance.
  • Established Samsung ecosystem integration.

  • Significantly shorter battery life.
  • Slower charging speed.
  • Lower reverse wireless charging power.

Asus Zenfone 12 Ultra

  • Exceptional battery endurance.
  • Ultra-fast 65W charging.
  • Higher peak display brightness.

  • Slightly lower CPU clock speed.
  • Less established brand recognition in some markets.
  • May require adapting to Asus’s software experience.

Display Comparison

The Asus Zenfone 12 Ultra immediately distinguishes itself with a measured peak brightness of 1965 nits, significantly exceeding the Samsung Galaxy S25’s 1395 nits. This translates to superior visibility in direct sunlight. While both likely employ LTPO technology for adaptive refresh rates (inferred from flagship positioning), the Zenfone’s higher brightness is a tangible advantage. The S25 may benefit from Samsung’s established color calibration expertise, but the Zenfone’s raw luminance is a compelling factor for outdoor use.

Camera Comparison

Context data lacks camera specifics, but given the flagship positioning, both devices will likely feature multi-camera systems. The Zenfone’s brand history suggests a focus on computational photography, while Samsung typically emphasizes vibrant, saturated image processing. Without sensor size or aperture information, it’s difficult to make a definitive judgment. However, the absence of mention of a high-resolution main sensor on either device suggests a focus on image quality over megapixel count, which is a positive trend.

Performance

Both the S25 and Zenfone 12 Ultra are powered by the Qualcomm SM8750-AC/AB Snapdragon 8 Elite (3nm), featuring an octa-core CPU configuration with 2x Oryon V2 Phoenix L cores at 4.47 GHz (S25) vs 4.32 GHz (Zenfone) and 6x Oryon V2 Phoenix M cores at 3.53 GHz on both. The slight clock speed difference in the S25’s prime cores suggests a marginal performance edge in CPU-intensive tasks, but real-world differences will likely be minimal. Both utilize LPDDR5x RAM (spec not provided, but standard for this tier). Thermal management will be crucial; the 3nm process should improve efficiency, but sustained loads will reveal which device handles heat more effectively.

Battery Life

The Asus Zenfone 12 Ultra dominates in battery endurance, offering a remarkable 61:00h rating compared to the S25’s 37:16h. This is coupled with an active use score of 15:50h for the Zenfone versus 13:09h for the S25. The Zenfone also boasts significantly faster charging at 65W (100% in 39 minutes) utilizing PD3.0, PPS, and QC5, while the S25 is limited to 25W (50% in 30 minutes) with PD3.0. The Zenfone’s 10W reverse wired charging also surpasses the S25’s 4.5W reverse wireless capability, offering more practical utility for topping up accessories.

Buying Guide

Buy the Samsung Galaxy S25 if you prioritize a vibrant, exceptionally bright display and seamless integration within the Samsung ecosystem. It’s ideal for media consumption and users heavily invested in Samsung services. Buy the Asus Zenfone 12 Ultra if you demand maximum battery life, lightning-fast charging, and a more aggressive value proposition, making it perfect for travelers, power users, and those who dislike frequent charging.

Frequently Asked Questions

❓ Does the Snapdragon 8 Elite in the Zenfone 12 Ultra throttle under sustained gaming loads, given its slightly lower CPU clock speed compared to the S25?
While the S25 has a marginally higher CPU clock speed, the Snapdragon 8 Elite’s 3nm process and the Zenfone 12 Ultra’s likely robust cooling system should mitigate throttling. The Zenfone’s larger battery also provides a thermal buffer, allowing it to maintain peak performance for longer periods during gaming sessions. Real-world testing will be needed to confirm, but the Zenfone is well-positioned to handle demanding games.
❓ How does the 2000 cycle battery life rating of the S25 compare to the 1200 cycles of the Zenfone 12 Ultra in terms of long-term battery health?
The S25’s 2000 cycle rating suggests it will maintain a higher percentage of its original capacity after two years of typical use compared to the Zenfone 12 Ultra. However, the Zenfone’s significantly larger battery capacity and superior endurance mean it will likely still offer more usable battery life overall, even with a lower cycle count. Cycle count is important, but total capacity and usage patterns are equally crucial.
❓ What wireless charging standards are supported by each device, and how does this impact compatibility with different wireless chargers?
The Samsung Galaxy S25 supports Qi2 wireless charging, ensuring compatibility with the latest generation of wireless chargers. The Asus Zenfone 12 Ultra supports the older Qi standard. While Qi2 is backwards compatible with Qi, Qi2 offers improved efficiency and safety features. Users with newer Qi2 chargers will benefit from faster and more reliable wireless charging with the S25.