OnePlus 15T vs Xiaomi 17 Ultra

OnePlus 15T

The 6.32-inch 165 Hz 1.5K AMOLED panel is the only true 165 Hz compact-flagship display on the market and pairs that refresh rate with a measured 1,800 nits brightness, 460 ppi pixel density, Crystal Shield Glass, and HDR10+/Dolby Vision support. Native 165 Hz support in popular FPS games is a real differentiator. Notebookcheck flags 120.7 Hz PWM dimming that can cause eyestrain for sensitive users.

• The 6.32-inch 165 Hz AMOLED panel achieves a very good 460 ppi pixel density and the advertised maximum brightness of 1,800 nits in standard measurement.
• Display sharpness is plenty competent — sharp, smooth, and easily one of the strongest spec sheets you can get on a compact phone.
• Native 165 Hz support in COD, Delta Force and Peacekeeper Elite makes this the only small-screen flagship pushing a full 165 Hz gaming experience.
• OnePlus claims up to 3,600 nits peak brightness — even on a playground in direct sunlight you can still see everything clearly, no squinting required.
• Specifications confirm a 6.32-inch 1.5K (1216 × 2640) resolution with 165 Hz refresh — a configuration unique to the 15T in the compact class.
• Display backlight flickers at just 120.7 Hz under PWM dimming — low enough that the flickering may cause eyestrain and headaches for sensitive users after extended use.

Xiaomi 17 Ultra

A 6.9-inch 1.5K LTPO AMOLED rated at 3,500 nits peak. Measured brightness is strong on small patches but middling full-screen, and one long-term user was pleasantly surprised by it.

• 6.9-inch M10 OLED LTPO flat display at 1.5K resolution, 120Hz, with up to 3,500 nits peak brightness, HDR10 and Dolby Vision.
• In automatic brightness the screen measured over 1,100 nits, rising to over 3,600 nits on a small patch of the screen.
• Manual full-screen white brightness reached only 675 nits in controlled testing — well below the headline peak figure.
• The display surprised one long-term user in a positive way — not at the level of the Pixel 10 Pro's panel, but still rather good.

OnePlus 15T

Snapdragon 8 Elite Gen 5 paired with 12-16GB LPDDR5X Ultra Pro RAM delivers flagship synthetic scores — Notebookcheck recorded Geekbench multi-core 10,976 and 3DMark Wild Life Unlimited 29,901, on par with the larger Xiaomi 17 and Honor Magic8 Pro Air. The problem is sustained: in the 3DMark Wild Life stress test the GPU drops over 50% and the back of the phone hits 50 °C, which both Notebookcheck and SuperSaf flag as a deal-breaker for long gaming sessions.

• Geekbench 6 multi-core hits 10,976 — flagship-tier and within 1% of the average 8 Elite Gen 5 result, so there is no compromise on the chipset versus larger phones.
• 3DMark Wild Life Unlimited hits 29,901 — 5% above the 8 Elite Gen 5 average and ahead of the Xiaomi 17 with the same chip.
• In the 3DMark stress tests the OnePlus 15T shows a sharp drop in performance of over 50%, which significantly lowers our rating.
• Wildlife Extreme stress test scores swung from 6,990 best loop to 3,743 worst loop in a single run — the chart is 'quite a bit of a bumpy ride' and performance mode did nothing to stabilize it.
• Surface temperatures hit 48.3 °C on the back during stress testing and continued climbing to 50 °C near the camera bump — about 45 °C internal — which seems to be the phone's thermal limit.
• Genshin Impact averaged 60.3 fps over 30 minutes at just 3.2 W power draw, with the phone staying cool to the touch — and Peacekeeper Elite pushed 164.5 fps thanks to native 165 Hz support.
• r/Android's reviewer thread flags the same thermal issue directly: 'Gets kinda hot, over 50 degrees in the corner. This is with its very heavy throttling.'

Xiaomi 17 Ultra

Snapdragon 8 Elite Gen 5 keeps it firmly in the flagship tier with strong gaming, though sustained behaviour and thermals draw mixed verdicts.

• The Snapdragon 8 Elite Gen 5 brings ~20% faster CPU, ~23% faster GPU and peak speeds up to 4.61GHz over the previous generation.
• The iPhone has a slight single-core edge but the Xiaomi takes the lead in Geekbench multi-core.
• Genshin Impact at very high settings ran 30 minutes at an average of 55.3fps with a 1% frame drop, while lighter titles like Honor of Kings averaged 107.8fps; both front and back stayed around 40°C.
• It delivered significantly better gaming performance than the Xiaomi 17 Pro and performed better in the stress test than the 17 Pro with the same 16GB of RAM.
• Delta Force ran for 23 minutes straight with impressive thermal management and no notable heating.

OnePlus 15T

This is the section the OnePlus 15T was built to win. The 7,500 mAh silicon-carbon 'Glacier' cell is the largest ever fitted to a true compact phone — 50% bigger than the iPhone 17's pack in a similar footprint. Notebookcheck measured roughly 1.5 days of real-world endurance at 150 cd/m². Wired charging tops out at 100 W, wireless at 50 W. The only friction points are the missing built-in magnets for MagSafe-style alignment and the still-USB-2.0 port.

• OnePlus relies on a silicon-carbon-based battery with a large capacity of 7,500 mAh for its mini flagship — in our practical battery test at 150 cd/m² brightness, the 15T achieved an excellent battery life of nearly 1.5 days.
• 9to5Google's preview confirms the 7,500 mAh cell carries the same 'Glacier' moniker as the OnePlus 15's battery, so the silicon-carbon structure is here too — 200 mAh more than the larger sibling.
• Even though the phone keeps the same compact size, it now packs a massive 7,500 mAh battery — to put that into perspective, the iPhone 17 Pro Max only has around 5,000 mAh, and this is a 6.32-inch phone.
• Battery life is wild for a phone this size and is actually a hair bigger than the one in the OnePlus 15, which has a noticeably larger footprint.
• 100W SuperVOOC wired charging and 50W wireless mean even the huge cell refills fast — getting through two full days on a single charge feels totally realistic.
• There is no native magnetic Qi alignment — wireless charging works, but accessories require a separate magnetic case for MagSafe-style snap-on functionality.
• r/Android's reaction to the battery is unambiguous — 'Incredible battery life makes the compact smartphone competition pale in comparison' is the actual review-thread headline.

Xiaomi 17 Ultra

The single biggest divide in the coverage: lab tests record an excellent active-use score, but the global model's smaller battery, ~10%/hour real-world drain and heat make endurance inconsistent. Charging stepped down to 90W wired / 50W wireless.

• The global 17 Ultra earned an excellent active-use battery score of over 19 hours, charging 0–70% in half an hour and to full in just 43 minutes.
• After 3 months a user still had around 45% battery left at the end of the day when not using the camera intensively.
• For a 6,000mAh battery, ~4 hours of screen-on time over a full day was disappointing — the S26 Ultra's 5,000mAh cell matched or beat it under the same camera-and-navigation use.
• In a head-to-head extreme test the 17 Ultra ran hotter and lost more battery than the OnePlus 15 and Oppo Find X9 Pro at nearly every stage, finishing about 8 hours 8 minutes at 43.7°C.
• The global model holds ~800mAh less than the China version and drains roughly 10% per hour, so it can't last a full 15-hour day the way the China version does.

OnePlus 15T

The OnePlus 15T ships with ColorOS 16 on Android 16 in China rather than the global OxygenOS, though the two skins are now nearly identical in feel. Update commitments are unclear — OnePlus doesn't publish a timeline for Chinese-market hardware, and even the global OnePlus 15 only commits to 4 years of major Android upgrades. Mind Space (AI-powered productivity vault) and Gemini integration are the headline software features.

• ColorOS 16 comes pre-installed on the 15T instead of OxygenOS — but the differences are minor overall, with German language and Android Auto supported, though no WearOS watches or eSIMs.
• There are question marks over the duration of the updates provided — the manufacturer does not usually provide any information on this for China, though typically a OnePlus 15-class phone should receive security updates for six years.
• OxygenOS 16 (and ColorOS 16 by extension) integrates Gemini with Mind Space — you can ask Gemini about any saved memory and it accesses local content to perform tasks, making it the best on-phone AI integration we have seen.
• Mind Space is the headline AI feature — a digital vault that takes a screenshot of important content and saves it as a card with URL, summary, title and hashtags for contextual search.
• The system feels incredibly smooth — arguably one of the best experiences you can get on Android right now, with useful features for students like meeting summaries and lecture transcription.
• Update commitment trails the competition — even on the global OnePlus 15 the company only promises 4 years of major Android upgrades, well behind Samsung and Google's 7-year commitments.

Xiaomi 17 Ultra

The phone's most consistent weakness. HyperOS is widely seen as not up to par with the hardware, with camera-app limitations and an iOS-clone feel — though a minority of long-term owners disagree.

• The 17 Ultra perfectly embodies a great camera held back by software — the HyperOS interface is seriously lagging and not up to par with the rest of the phone.
• Android Police's verdict: the best camera phone of 2026 has a serious problem.
• Camera-app software limitations frustrated reviewers — quick-launch buried in gesture settings and the ultrawide preview looking awful.
• After 3 months one owner called HyperOS 3 one of the best versions of Xiaomi software they've used, with 6 years of security support.
• Even fans note HyperOS hasn't visibly evolved in years and Xiaomi should work on the software more.