Samsung Galaxy S25 Ultra vs Xiaomi 15

Samsung Galaxy S25 Ultra

The 6.9-inch Dynamic AMOLED 2X display with 2600 nit peak brightness and anti-reflective coating is universally praised as the best smartphone display available.

• 2600 nit peak brightness with anti-reflective coating makes it the most sunlight-readable phone
• 120Hz LTPO refresh rate is butter smooth with excellent touch response

Xiaomi 15

The 6.36-inch 1.5K LTPO OLED is sharp, vibrant, and incredibly bright at 3,200 nits peak (tested up to 3,593 nits HDR). Ultra-narrow 1.38mm bezels and high-frequency PWM dimming above 3,000Hz round out an excellent display package, though OLED smear at lower brightness is a noted concern.

• Peak brightness tested at 3,593 nits in HDR — among the brightest compact phone displays available
• Ultra-narrow 1.38mm bezels with excellent color accuracy in Original Color PRO profile
• OLED smear visible at lower brightness levels (0-70% range) — a recurring user complaint

Samsung Galaxy S25 Ultra

The quad camera system features an improved 200MP main sensor, 50MP ultrawide, 10MP 3x telephoto, and 50MP 5x periscope. Galaxy AI enhances post-processing significantly.

• 200MP main sensor produces incredibly detailed shots with improved noise handling
• Galaxy AI photo editing (Generative Edit, Best Face) is genuinely useful and well-implemented
• Video recording improvements with LOG support appeal to content creators
• Night mode still trails iPhone 16 Pro in very low light scenarios

Xiaomi 15

The triple 50MP Leica system shines with its main sensor and improved 2.6x telephoto, earning a DxOMark score of 146. Leica color profiles produce natural, pleasing images with excellent dynamic range. The ultrawide camera is the clear weakness, with noticeably more noise in low light and no autofocus.

• 50MP main Leica Summilux camera delivers excellent photo quality with natural colors and strong dynamic range
• 2.6x optical telephoto is a meaningful upgrade over the Xiaomi 14 — sharp and versatile
• Ultrawide camera is the weakest link — subpar quality, no autofocus, noticeably more noise in low light
• DxOMark camera score of 146 — good but not class-leading among 2025 flagships

Samsung Galaxy S25 Ultra

Snapdragon 8 Elite delivers the fastest Android performance available with excellent efficiency. 12GB RAM handles multitasking and AI workloads effortlessly.

• Snapdragon 8 Elite is a beast — fastest Android chip with significant efficiency gains
• On-device AI processing is noticeably faster than cloud-based alternatives
• Thermals are well-managed with the larger vapor chamber — no throttling in sustained use

Xiaomi 15

The Snapdragon 8 Elite with 12GB RAM delivers flagship-tier performance that's smooth and snappy for everyday use, gaming, and multitasking. However, the compact body struggles to dissipate heat under sustained loads, causing notable thermal throttling during extended gaming sessions.

• Snapdragon 8 Elite scores ~2,990 single-core and ~9,114 multi-core on Geekbench 6 — genuinely fast
• Thermal throttling is a real issue — fails to complete 3DMark GPU stress tests and gets uncomfortably hot
• CPU throttles to 72-77% of peak under sustained load — compact chassis limits cooling capacity

Samsung Galaxy S25 Ultra

The 5000mAh battery paired with Snapdragon 8 Elite efficiency delivers solid all-day battery life, though charging speeds remain conservative.

• Easily lasts a full day with heavy use, and two days with moderate use
• 45W wired charging is adequate but slow compared to OnePlus and Xiaomi offerings

Xiaomi 15

A standout category for the Xiaomi 15. The 5,400mAh silicon-carbon battery is a huge upgrade from the Xiaomi 14's 4,610mAh, delivering 16+ hours of active use in GSMArena's tests and consistently 7-8 hours of screen-on time. 90W wired charging goes from 0-100% in about 50 minutes.

• GSMArena Active Use Score of 16:28 hours — excellent endurance for a compact flagship
• 5,400mAh silicon-carbon battery is a massive upgrade from the Xiaomi 14's 4,610mAh — real-world 7-8 hours SOT
• 90W wired charging does 0-100% in about 50 minutes; 50W wireless charging also supported