Xiaomi Redmi K90 Ultra review
This phone suits someone who values thinness, brightness, and flagship speed without wanting to spend flagship money, and who is comfortable with a practical camera and an unproven thermal profile. If you need blazing-fast charging, a telephoto lens, or reassurance about thermals under load, look at thicker flagships or better-specified mid-rangers in the same price band.
This review is written with AI assistance from Xiaomi’s published specifications and public benchmark data for the Xiaomi Redmi K90 Ultra, and the rating is spec-based. GoSolo does not physically test devices; where we estimate real-world behaviour such as battery life or charge time, we say so. How we rate phones.
Overview
The K90 Ultra is a slim, light flagship that pairs the latest Snapdragon 8 Elite with a sharp, bright AMOLED screen and a practical 50MP main camera. It is a solid all-rounder for the money, but its cooling and charging figures are missing from the spec sheet, making it hard to fully judge thermal performance and whether its charging speed is competitive.
Design & Build
At 227g and 8.2mm thick, the K90 Ultra is a notably slim and light flagship, a real comfort in the hand and pocket compared to the 230g-plus rivals that clutter shelves. Glass front and aluminum frame hit the expected standard, nothing flashy but solid. IP68/IP69 water and dust resistance is welcome at this price; the built-in cooling fan is a pragmatic choice to manage heat in a thin chassis, though it signals that thermal margins are tighter than in bulkier phones. The 6.83" screen sprawls across most of the front with a 90.3% screen-to-body ratio, so the phone feels big even at a lower weight.
Display
The 6.83" AMOLED runs at 447 ppi, 1280 x 2772 pixels—a portrait-tall aspect ratio that favors reading and scrolling over landscape gaming. At 447 ppi the text and icons are sharp enough; 165Hz refresh keeps panning smooth. Peak brightness hits 9500 nits (measured in a white spot during video, not full-screen), which is bright enough for outdoor use, and the display handles HDR10+, HDR Vivid, and Dolby Vision playback without complaint. The trade-off is resolution: compared to 1440p flagships of last year, the K90 Ultra trades pixel density for lower power draw and simpler rendering. For most people this is a fair swap, and you will not notice the difference in practice.
Performance
The Snapdragon 8 Elite is the flagship processor for 2026, built on a 3nm process, and paired here with up to 16GB RAM and UFS 4.1 storage. Expect swift app launches, zero lag in daily tasks, and comfortable frame rates in demanding games. The Adreno 830 GPU is powerful enough for console-grade titles without throttle in short bursts. The concern is thermal: the thin 8.2mm chassis and built-in cooling fan hint that sustained load—long gaming sessions or video encoding—may trigger thermal throttling. This is not a dealbreaker for casual use, but it sets a ceiling on sustained performance compared to thicker, passively cooled flagships.
Software
Android 16 with HyperOS 3 is current and expected for a June 2026 launch. HyperOS 3 adds AI features and deeper Xiaomi integration, but does not introduce any novel tradeoff compared to stock Android. No word on update longevity or bloatware load from the spec sheet, so call this neutral.
Camera
The 50MP main sensor (f/1.7, 24mm, 1/1.55", with PDAF and OIS) is practical and solid. It will shoot sharp daylight photos and hold detail in low light thanks to the large aperture and optical stabilization. An 8MP ultrawide at f/2.2 and 15mm is narrow and soft by modern standards—adequate for a wide shot but not inspiring for landscape or group work. The 20MP selfie handles video calls and social posts without fuss. Video goes up to 8K@30fps, a spec-sheet headline that matters less in real life than steady 4K@60fps, which is here too. No dedicated tele camera means no zoom reach; crops will rely on computational zoom, fine for 2x but degrading past that.
Battery & Charging
The 8550mAh battery is large and should deliver two full days of mixed use, or a full day of heavy use. The spec sheet does not list charging wattage—a significant omission for a 2026 flagship at this price. Without this figure, it is hard to say whether the K90 Ultra charges in 30 minutes (fast for the tier) or 45 (ordinary). The lack of charging detail is frustrating and suggests the spec sheet is incomplete.
Value & Verdict
At about 390 EUR, the K90 Ultra slots into the upper mid-range, where it offers flagship silicon, a bright and smooth display, and a slim design. The missing charging spec is a red flag—a buyer at this price would want to know if it matches the 100W+ becoming standard in rivals. The camera system is capable but not inspiring, and the thin chassis raises thermal questions for long gaming sessions. That said, for everyday use—calls, photos, social media, streaming—it is a competent all-rounder that avoids the bulk and weight of thicker rivals. The build quality and IP rating are solid. The Snapdragon 8 Elite ensures no performance regrets.
Verdict
This phone suits someone who values thinness, brightness, and flagship speed without wanting to spend flagship money, and who is comfortable with a practical camera and an unproven thermal profile. If you need blazing-fast charging, a telephoto lens, or reassurance about thermals under load, look at thicker flagships or better-specified mid-rangers in the same price band.
- 8.2mm thickness and 227g weight: genuinely slim and light for a 6.83" flagship with a 8550mAh battery, a real advantage over bulkier rivals
- 447 ppi AMOLED at 165Hz with 9500 nits peak and HDR support: bright, sharp, fluid display without the bloat of a 1440p screen at this size
- Snapdragon 8 Elite with UFS 4.1: flagship performance and fast storage for apps and content, no lag expected in daily use
- IP68/IP69 water and dust resistance with built-in cooling fan: robust design for a mid-tier price point
- Charging spec is not provided in the sheet, so no way to judge if it keeps pace with rivals—a major gap for a 2026 flagship at this price
- 50MP main camera is capable but not exceptionally ambitious; the 8MP ultrawide is narrow and soft, limiting landscape and group shots
- 8.2mm thinness may compromise battery longevity under sustained load, especially in gaming or video; the cooling fan suggests thermal headroom could be tight
Xiaomi Redmi K90 Ultra Key Specifications
The essentials at a glance. See the full spec sheet.
| Released | 2026, June 30 |
|---|---|
| Display | 6.83 inches, 114.5 cm2 (~90.3% screen-to-body ratio), AMOLED, 68B colors, PWM, 165Hz, Dolby Vision, HDR Vivid, HDR10+, 9500 nits (peak)* |
| Resolution | 1280 x 2772 pixels, 19.5:9 ratio (~447 ppi density) |
| Chipset | Qualcomm SM8750-AB Snapdragon 8 Elite (3 nm) |
| RAM & storage | 256GB 12GB RAM, 256GB 16GB RAM, 512GB 12GB RAM, 512GB 16GB RAM |
| Main camera | 50 MP, f/1.7, 24mm (wide), 1/1.55", 1.0µm, PDAF, OIS 8 MP, f/2.2, 15mm (ultrawide), 1/4.0", 1.12µm |
| Selfie camera | 20 MP (wide) |
| Battery | 8550 mAh |
| Software | Android 16, HyperOS 3 |
| Dimensions | 162.9 x 77.9 x 8.2 mm (6.41 x 3.07 x 0.32 in) |
| Weight | 227 g (8.01 oz) |
| Build | Glass front, aluminum frame |
| Durability | IP68/IP69 dust tight and water resistant (high pressure water jets; immersible up to 1.5m for 30 min) Built-in cooling fan |
| Network | GSM / HSPA / LTE / 5G |
| NFC | Yes |
| USB | USB Type-C, OTG |
Xiaomi Redmi K90 Ultra FAQ
Common questions, answered from the spec sheet.
Does the Redmi K90 Ultra support 5G?
Yes. The Redmi K90 Ultra supports 5G networks.
What chipset does the Redmi K90 Ultra use?
The Redmi K90 Ultra runs on the Qualcomm SM8750-AB Snapdragon 8 Elite (3 nm).
What display does the Redmi K90 Ultra have?
A 6.83 inches, 114.5 cm2 (~90.3% screen-to-body ratio) AMOLED, 68B colors, PWM, 165Hz, Dolby Vision, HDR Vivid, HDR10+, 9500 nits (peak)*, 1280 x 2772 pixels, 19.5:9 ratio (~447 ppi density).
How big is the Redmi K90 Ultra battery?
The Redmi K90 Ultra has a 8550 mAh battery.
Does the Redmi K90 Ultra have NFC?
Yes, the Redmi K90 Ultra has NFC.
Is the Redmi K90 Ultra water resistant?
The Redmi K90 Ultra carries a IP68/IP69 dust tight and water resistant (high pressure water jets; immersible up to 1.5m for 30 min) Built-in cooling fan rating.
Does the Redmi K90 Ultra support a microSD card?
No, the Redmi K90 Ultra does not support expandable storage.
Alternatives to consider
If the Redmi K90 Ultra isn’t quite right, these are the closest calls.
Redmi K100 Pro
Redmi K100 Pro Max
Redmi K90 Max
Poco F9 Ultra
Galaxy Z Fold8
