Xiaomi 15 vs Samsung Galaxy S25 Ultra: A Deep Dive into Performance and Endurance

The Xiaomi 15 and Samsung Galaxy S25 Ultra represent the pinnacle of Android flagship technology, both powered by the latest Qualcomm Snapdragon 8 Elite. However, they diverge significantly in their approach to battery life, charging speed, and overall user experience. This comparison dissects the key differences to help you choose the device that best suits your needs.
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🏆 Quick Verdict

For the average user prioritizing longevity and rapid replenishment, the Xiaomi 15 emerges as the winner. Its exceptional 63:26h battery endurance and 90W charging significantly outperform the S25 Ultra’s 44:54h and 45W, making it ideal for power users and travelers.

PHONES
Phone Names Xiaomi 15 Samsung Galaxy S25 Ultra
Network
2G bandsGSM 850 / 900 / 1800 / 1900GSM 850 / 900 / 1800 / 1900
3G bandsHSDPA 800 / 850 / 900 / 1700(AWS) / 1900 / 2100HSDPA 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, 42, 48, 66 - International1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28, 32, 38, 39, 40, 41, 66 - International
5G bands1, 2, 3, 5, 7, 8, 12, 20, 25, 26, 28, 38, 40, 41, 48, 66, 75, 77, 78 SA/NSA - International1, 2, 3, 5, 7, 8, 12, 20, 25, 26, 28, 38, 40, 41, 66, 75, 77, 78 SA/NSA/Sub6 - International
SpeedHSPA, LTE, 5GHSPA, LTE (up to 7CA), 5G
TechnologyGSM / HSPA / LTE / 5GGSM / CDMA / HSPA / EVDO / LTE / 5G
Launch
Announced2024, October 292025, January 22
StatusAvailable. Released 2024, October 29Available. Released 2025, February 03
Body
BuildGlass front (Xiaomi Shield Glass), aluminum alloy frame (6M42)Glass front (Corning Gorilla Armor 2), glass back (Gorilla Glass Victus 2), titanium frame (grade 5)
Dimensions152.3 x 71.2 x 8.1 / 8.4 / 8.5 mm162.8 x 77.6 x 8.2 mm (6.41 x 3.06 x 0.32 in)
SIM· Nano-SIM + Nano-SIM· Nano-SIM + Nano-SIM + eSIM + eSIM (max 2 at a time)· 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 - CN
Weight189 / 191 / 192 g (6.67 oz)218 g (7.69 oz)
Display
ProtectionXiaomi Shield Glass, Mohs level 6Corning Gorilla Armor 2, Mohs level 6
Resolution1200 x 2670 pixels, 20:9 ratio (~460 ppi density)1440 x 3120 pixels, 19.5:9 ratio (~498 ppi density)
Size6.36 inches, 97.6 cm2 (~90.0% screen-to-body ratio)6.9 inches, 116.9 cm2 (~92.5% screen-to-body ratio)
TypeLTPO AMOLED, 68B colors, 1920Hz PWM, 120Hz, Dolby Vision, HDR10+, 3200 nits (peak)Dynamic LTPO AMOLED 2X, 120Hz, HDR10+, 2600 nits (peak)
Platform
CPUOcta-core (2x4.32 GHz Oryon V2 Phoenix L + 6x3.53 GHz Oryon V2 Phoenix M)Octa-core (2x4.47 GHz Oryon V2 Phoenix L + 6x3.53 GHz Oryon V2 Phoenix M)
ChipsetQualcomm SM8750-AB Snapdragon 8 Elite (3 nm)Qualcomm SM8750-AC Snapdragon 8 Elite (3 nm)
GPUAdreno 830Adreno 830 (1200 MHz)
OSAndroid 15, up to 4 major Android upgrades, HyperOS 2Android 15, up to 7 major Android upgrades, One UI 7
Memory
Card slotNoNo
Internal256GB 12GB RAM, 256GB 16GB RAM, 512GB 12GB RAM, 512GB 16GB RAM, 1TB 16GB RAM256GB 12GB RAM, 512GB 12GB RAM, 1TB 12GB RAM, 1TB 16GB RAM
Main Camera
FeaturesLaser AF, color spectrum sensor, Leica lens, Dual-LED dual-tone flash, HDR, panoramaLaser AF, Best Face, LED flash, auto-HDR, panorama
Quad-200 MP, f/1.7, 24mm (wide), 1/1.3", 0.6µm, multi-directional PDAF, OIS 10 MP, f/2.4, 67mm (telephoto), 1/3.52", 1.12µm, PDAF, OIS, 3x optical zoom 50 MP, f/3.4, 111mm (periscope telephoto), 1/2.52", 0.7µm, PDAF, OIS, 5x optical zoom 50 MP, f/1.9, 120˚ (ultrawide), 1/2.5", 0.7µm, dual pixel PDAF, Super Steady video
Triple50 MP, f/1.6, 23mm (wide), 1/1.31", 1.2µm, dual pixel PDAF, OIS 50 MP, f/2.0, 60mm (telephoto), 1/2.76", 0.64µm, PDAF (10cm - ∞), OIS, 2.6x optical zoom 50 MP, f/2.2, 14mm, 115˚ (ultrawide), 1/2.76", 0.64µm-
Video8K@24/30fps (HDR), 4K@24/30/60fps (HDR10+, 10-bit Dolby Vision HDR, 10-bit LOG), 1080p@30/60/120/240/960fps, 720p@1920fps, gyro-EIS8K@24/30fps, 4K@30/60/120fps, 1080p@30/60/120/240fps, 10-bit HDR, HDR10+, stereo sound rec., gyro-EIS
Selfie camera
FeaturesHDR, panoramaHDR, HDR10+
Single32 MP, f/2.0, 21mm (wide), 1/3.14", 0.7µm12 MP, f/2.2, 26mm (wide), 1/3.2", 1.12µm, dual pixel PDAF
Video4K@30/60fps, 1080p@30/60fps, HDR10+, gyro-EIS4K@30/60fps, 1080p@30fps
Sound
35mm jackNoNo
Loudspeaker Yes, with stereo speakersYes, with stereo speakers
Comms
Bluetooth5.4/6.0, A2DP, LE, aptX HD, aptX Adaptive, LHDC 55.4, A2DP, LE
Infrared portYes-
NFCYesYes
PositioningGPS (L1+L5), GLONASS (G1), BDS (B1I+B1c+B2a), GALILEO (E1+E5a), QZSS (L1+L5)GPS, GLONASS, BDS, GALILEO, QZSS
RadioNoNo
USBUSB Type-C 3.2, Display Port, OTGUSB Type-C 3.2, DisplayPort 1.2, OTG
WLANWi-Fi 802.11 a/b/g/n/ac/6e/7, dual-band or 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, proximity, gyro, compass, barometerFingerprint (under display, ultrasonic), accelerometer, gyro, proximity, compass, barometer
Battery
Charging90W wired, PD3.0, QC3+ 50W wireless 10W reverse wireless45W wired, PD3.0, 65% in 30 min 15W wireless (Qi2 Ready) 4.5W reverse wireless
TypeMarket-dependent versions:· Si/C Li-Ion 5240 mAh - Global· Si/C Li-Ion 5400 mAh - ChinaLi-Ion 5000 mAh
Misc
ColorsBlack, White, Liquid Silver, Green, LilacTitanium Silver Blue, Titanium Black, Titanium White Silver, Titanium Gray, Titanium Jade Green, Titanium Jet Black, Titanium Pink Gold
Models24129PN74G, 24129PN74I, 24129PN74CSM-S938B, SM-S938B/DS, SM-S938U, SM-S938U1, SM-S938W, SM-S938N, SM-S9380, SM-S938E, SM-S938E/DS
Price$ 789.99 / £ 519.00 / € 648.25€ 895.00 / $ 859.98 / £ 799.99 / ₹ 110,498
SAR-1.26 W/kg (head)     0.64 W/kg (body)
SAR EU0.99 W/kg (head)     1.00 W/kg (body)1.25 W/kg (head)     1.42 W/kg (body)
EU LABEL
Battery63:26h endurance, 1000 cycles44:54h endurance, 2000 cycles
EnergyClass AClass B
Free fallClass C (90 falls)Class A (270 falls)
RepairabilityClass CClass C

Xiaomi 15

  • Exceptional battery life (63:26h endurance)
  • Ultra-fast 90W wired charging
  • Higher peak display brightness (1517 nits)

  • Fewer battery charge cycles (1000)
  • Potentially less refined software experience compared to Samsung

Samsung Galaxy S25 Ultra

  • Slightly faster CPU clock speeds
  • Longer battery lifespan (2000 charge cycles)
  • Samsung’s established ecosystem and software features

  • Significantly shorter battery endurance (44:54h)
  • Slower wired charging (45W)

Display Comparison

Both the Xiaomi 15 and Samsung Galaxy S25 Ultra feature high-end displays, with the Xiaomi 15 achieving a measured peak brightness of 1517 nits, slightly surpassing the S25 Ultra’s 1417 nits. While the difference isn’t massive, the Xiaomi 15’s higher brightness will be noticeable in direct sunlight. Both likely employ LTPO technology for adaptive refresh rates, though this isn’t specified. The S25 Ultra’s display benefits from Samsung’s established color calibration expertise, but the Xiaomi 15’s brightness advantage is a key differentiator.

Camera Comparison

While detailed camera specs are absent, the focus should be on image processing and sensor quality. Given Samsung’s history, the S25 Ultra likely prioritizes vibrant, saturated colors, while Xiaomi often aims for a more natural look. The absence of sensor details makes a direct comparison difficult, but the S25 Ultra’s reputation for camera innovation suggests a potential advantage in computational photography. The lack of mention of high-resolution sensors or advanced zoom capabilities on either device suggests a focus on overall image quality rather than megapixel count.

Performance

Both devices are powered by the Qualcomm SM8750-AB/AC Snapdragon 8 Elite (3nm), featuring an octa-core CPU configuration with 2x Oryon V2 Phoenix L cores at 4.32 GHz (Xiaomi 15) vs 4.47 GHz (S25 Ultra) and 6x Oryon V2 Phoenix M cores at 3.53 GHz on both. The S25 Ultra’s marginally higher clock speed on the prime cores translates to a slight performance edge in CPU-intensive tasks, but the real-world difference will be minimal for most users. Both utilize LPDDR5x RAM, and thermal management will be crucial to sustaining peak performance; the 3nm process should aid in efficiency.

Battery Life

The Xiaomi 15’s battery endurance of 63:26h is a standout feature, significantly exceeding the Samsung Galaxy S25 Ultra’s 44:54h. This translates to nearly a full day and a half of additional usage. The Xiaomi 15 also boasts 90W wired charging, capable of rapidly replenishing the battery, alongside 50W wireless and 10W reverse wireless charging. The S25 Ultra’s 45W wired charging, while still fast, is considerably slower. The S25 Ultra’s 2000 charge cycles are double that of the Xiaomi 15’s 1000, suggesting a longer lifespan for the battery itself, potentially offsetting the shorter overall endurance.

Buying Guide

Buy the Xiaomi 15 if you need all-day battery life and the fastest possible charging speeds, prioritizing endurance over marginal performance gains. It’s the perfect choice for users who frequently travel, game on the go, or simply dislike battery anxiety. Buy the Samsung Galaxy S25 Ultra if you prefer a slightly faster CPU for demanding tasks and value Samsung’s established ecosystem and software features, accepting a trade-off in battery endurance and charging speed.

Frequently Asked Questions

❓ Does the Xiaomi 15’s 90W charging generate excessive heat during prolonged use?
While 90W charging is fast, the Xiaomi 15 incorporates advanced thermal management systems to mitigate heat buildup. The 3nm Snapdragon 8 Elite also contributes to improved thermal efficiency, preventing significant throttling during charging or demanding tasks. However, some warmth is expected during rapid charging.
❓ How does the Samsung Galaxy S25 Ultra’s 2000 battery cycle rating impact long-term usability?
The S25 Ultra’s 2000 charge cycles indicate a longer expected battery lifespan before significant degradation. This means the battery will retain a higher percentage of its original capacity after two years of typical use compared to the Xiaomi 15. However, the Xiaomi 15’s superior initial endurance may still provide a better overall experience during that timeframe.
❓ Will the slight CPU clock speed difference between the two phones be noticeable in everyday tasks?
The 0.15 GHz difference in CPU clock speed is unlikely to be perceptible in most everyday tasks like browsing, social media, or video playback. The difference will be more apparent in highly demanding applications like video editing or 3D rendering, but even then, the margin will be relatively small.