Samsung Galaxy S25 Ultra vs Xiaomi 17 Ultra: Which to Buy?

Samsung's Galaxy S25 Ultra and Xiaomi's 17 Ultra are two of the most complete Android phones you can buy, and on the spec sheet they look almost like twins. Look closer, though, and they pull in different directions: the Galaxy is the versatile, do-everything flagship with an S Pen and the widest zoom range, while the Xiaomi is a camera-first phone built around a large main sensor, a huge battery and rapid charging. This comparison draws only on the complete published reviews of each phone; Truthful Reviews has not independently tested either handset.

Design and Build

The two are nearly identical in the hand. The Galaxy S25 Ultra measures 162.8 mm tall, 77.6 mm wide and 8.2 mm thick at 218 g, while the Xiaomi 17 Ultra is 162.9 mm tall, 77.6 mm wide and 8.3 mm thick at 218.4 g. Both carry an IP68 rating for dust and water resistance. Samsung's card is its integrated S Pen and Samsung DeX desktop mode, which push it toward productivity, though the S Pen has lost its Bluetooth remote features this generation and the flat frame's sharp edges can dig into the palm. Xiaomi wraps its phone in Shield Glass 3.0. If you write, sketch or want a phone that doubles as a light desktop, the Galaxy is unmatched here.

Display

Both use a 6.9-inch AMOLED panel at 120 Hz, but they optimise for different things. The Galaxy is the sharper of the two, running at a Quad HD+ 3120 x 1440 resolution for 498 ppi. The Xiaomi answers with brightness: its screen is rated among the brightest on the market, which pays off in harsh sunlight. So the choice is sharpness versus outright luminance — the Galaxy for pixel density, the Xiaomi for daylight visibility.

Performance

Both run Qualcomm's Snapdragon 8 Elite, but the Xiaomi 17 Ultra uses the newer Snapdragon 8 Elite Gen 5 paired with 16 GB of RAM, against the Galaxy's Snapdragon 8 Elite and 12 GB. The Galaxy offers 256 GB, 512 GB and 1 TB storage tiers; the Xiaomi comes in 512 GB and 1 TB. In everyday use both are effortlessly fast, and Samsung's One UI 7 is fluid and well thought out, if deliberately cautious rather than cutting-edge. The Xiaomi's newer silicon edges ahead on paper, but it warms slightly under sustained gaming and slips to the back of the pack in the most demanding ray-tracing tests, so its lead is narrower in practice than the generation gap suggests.

Cameras

This is where the two phones make their clearest pitch. The Galaxy S25 Ultra fields a versatile four-camera array: a 200 MP main sensor, a 50 MP ultra-wide, a 50 MP periscope for 5x optical zoom and a 10 MP telephoto for 3x, plus a 12 MP front camera and 8K video. Its zoom reach and video flexibility remain a genuine strength. The Xiaomi 17 Ultra takes the photographer's route: its 50 MP main camera sits behind a large Type 1-inch sensor at an equivalent 23 mm (f/1.7), joined by a 200 MP periscope telephoto at an equivalent 100 mm and a 50 MP ultra-wide at an equivalent 14 mm, with a 50 MP selfie camera and an optional pro photography kit. In short, the Galaxy wins on zoom versatility and video, while the Xiaomi leans on a bigger main sensor for image quality — it is squarely aimed at being the camera phone to beat.

Battery and Charging

The Xiaomi takes this category decisively. It packs a 6000 mAh battery against the Galaxy's 5000 mAh, and its endurance is rated as excellent. Charging is even more lopsided: the Xiaomi accepts 90 W wired and 50 W wireless charging, while the Galaxy tops out at 45 W wired — a rate reviewers now consider behind the competition — and 15 W wireless. If long battery life and fast top-ups are priorities, the Xiaomi has a clear, measurable lead.

Software and Extras

The Galaxy S25 Ultra runs Android 15 under One UI 7, with Galaxy AI and Gemini features woven throughout, plus Samsung's long track record of extended software support — a real advantage for anyone keeping a phone for years. The Xiaomi 17 Ultra runs the newer Android 16 under HyperOS 3, which is capable but a little cluttered. Beyond software, the Galaxy's S Pen, DeX and 8K recording form an ecosystem the Xiaomi does not try to match.

Which Should You Buy?

Choose the Samsung Galaxy S25 Ultra if you want the most versatile flagship: the integrated S Pen, DeX, the widest zoom range with dual telephoto lenses, 8K video, a sharper 1440p display and long software support — accepting only 45 W charging, a 5000 mAh battery that rivals now beat and a design that plays it safe. Choose the Xiaomi 17 Ultra if the camera and stamina lead: a large 1-inch main sensor, a 200 MP periscope, the brightest screen of the pair, a bigger 6000 mAh battery and far faster 90 W charging — accepting a busier interface and a chip that flags under the most extreme graphics loads. Neither is simply the better phone: the Galaxy is the all-round productivity powerhouse, and the Xiaomi is the battery-and-camera specialist.