Xiaomi 15 Ultra VS Xiaomi Redmi K90 Pro Max

Both the Xiaomi 15 Ultra and the Redmi K90 Pro Max share the same IP68 waterproof rating, meaning neither has an advantage in terms of protection against dust and water immersion. Neither offers a rugged build or a foldable form factor, so they are squarely comparable as standard flagship-style slabs.

Where they diverge meaningfully is in physical dimensions. The K90 Pro Max is notably slimmer at 7.9 mm versus the 15 Ultra's 9.4 mm — a 1.5 mm difference that is very perceptible in daily handling and in-pocket comfort. It is also lighter at 218 g compared to 229 g, and despite having a slightly taller and wider footprint, its overall volume is considerably smaller at 100.4 cm³ versus 114.2 cm³. This suggests the 15 Ultra packs more internal hardware density — likely a larger battery or more complex camera module — which accounts for its thicker, heavier chassis. The 15 Ultra, however, is slightly narrower (75.3 mm vs 77.8 mm), which can make one-handed reach marginally easier.

On design ergonomics, the Redmi K90 Pro Max has a clear edge: it is lighter, significantly thinner, and occupies less total volume, making it the more pocketable and comfortable device for extended use. The 15 Ultra's added bulk is likely a trade-off for what it carries internally, but purely from a physical design standpoint, the K90 Pro Max feels like the more refined carry.

The sharpness gap between these two screens is the headline story. The Xiaomi 15 Ultra delivers a 522 ppi pixel density at a 1440 x 3200 resolution, versus the Redmi K90 Pro Max's 416 ppi at 1200 x 2608 — a difference of over 100 ppi. At typical viewing distances this translates to visibly crisper text, finer detail in photos, and a more premium feel when reading or browsing. The K90 Pro Max's larger 6.9″ panel (vs 6.73″) gives it more screen real estate, but that advantage is partially offset by its lower pixel density, which becomes apparent on close inspection.

Interestingly, the K90 Pro Max counters with a 480Hz touch sampling rate compared to the 15 Ultra's 300Hz. For everyday use the difference is imperceptible, but in fast-paced gaming scenarios, the higher sampling rate means the display registers touch inputs more frequently, translating to marginally faster in-game response. The K90 Pro Max also includes branded damage-resistant glass — a spec the 15 Ultra lacks — offering a practical edge in scratch and drop resistance that matters for long-term durability. Both panels are otherwise identically matched: OLED/AMOLED, 120Hz refresh, HDR10+, Dolby Vision, and Always-On Display.

The conclusion depends on use case. For content consumption — especially photo viewing, reading, or video at close range — the 15 Ultra's display has a clear edge thanks to its superior resolution and sharpness. But for gamers and users who prioritize screen protection and raw input responsiveness, the K90 Pro Max's touch sampling rate and protective glass make a compelling case.

On paper, these two phones look nearly identical in performance — same 16GB RAM, same storage, same architecture, same Geekbench 6 scores. But the chipset names reveal a generational split: the Xiaomi 15 Ultra runs on the Snapdragon 8 Elite, while the Redmi K90 Pro Max packs the newer Snapdragon 8 Elite Gen 5. That distinction cascades into real differences: the K90 Pro Max's performance cores clock higher at 4.6 GHz versus 4.32 GHz, and its GPU runs at 1200 MHz versus the 15 Ultra's 1100 MHz.

The AnTuTu benchmark makes the gap impossible to ignore — 4,350,000 for the K90 Pro Max against 2,746,580 for the 15 Ultra, a difference of roughly 58%. AnTuTu is a composite score that stresses CPU, GPU, memory, and UX subsystems together, so a gap of this magnitude points to a substantially more capable chip in sustained workloads, GPU-intensive gaming, and AI processing tasks. The identical Geekbench single and multi-core results are curious and suggest the CPU cores perform similarly in short burst workloads, but the AnTuTu delta reflects the K90 Pro Max pulling significantly further ahead under sustained or GPU-heavy conditions.

The Redmi K90 Pro Max holds a clear performance advantage in this group. Shared fundamentals like RAM speed, memory bandwidth, and thermal envelope mean day-to-day tasks feel equivalent, but for demanding games, heavy multitasking, or future-proofing, the newer chip in the K90 Pro Max is the stronger foundation by a meaningful margin.

The camera systems diverge significantly in ambition. The Xiaomi 15 Ultra fields a four-lens array headlined by a 200MP main sensor, supplemented by three 50MP lenses — giving it extraordinary flexibility across focal lengths and lighting scenarios. The Redmi K90 Pro Max takes a more conventional route with a triple 50MP setup. While the K90 Pro Max's primary lens offers a wider aperture at f/1.7 versus the 15 Ultra's main lens at f/2.6 — an advantage in pure low-light capture on that one sensor — the 15 Ultra's secondary lenses reach as wide as f/1.6, and the sheer resolution headroom of a 200MP sensor enables far more aggressive cropping and detail recovery in post.

For zoom, the K90 Pro Max edges ahead with 5x optical zoom versus the 15 Ultra's 4.3x, a modest but real advantage for distant subjects. Video enthusiasts, however, will find the 15 Ultra considerably more capable: it supports HDR10 and Dolby Vision recording — formats the K90 Pro Max lacks entirely — which matters for anyone shooting footage intended for high-end displays or professional workflows. The 15 Ultra also retains manual shutter speed control, giving photographers finer creative control that the K90 Pro Max omits.

Taken together, the 15 Ultra holds a clear camera advantage. Its fourth lens, 200MP resolution, richer video codec support, and broader manual controls make it the more versatile and capable imaging platform. The K90 Pro Max is no slouch — its wider primary aperture and slightly longer optical zoom are genuine strengths — but the 15 Ultra outguns it across the majority of shooting scenarios.

The software story here is one of near-total parity with one meaningful split. The Redmi K90 Pro Max ships on Android 16 while the Xiaomi 15 Ultra runs Android 15 — a generational difference that gives the K90 Pro Max access to the latest platform security patches, behavioral improvements, and any Android 16-specific APIs that apps may increasingly target over time. For users who care about longevity and staying current, launching on a newer OS version is a tangible head start.

Flip through the rest of the feature list and the two phones are remarkably alike. Both offer the same privacy controls, dynamic theming, on-device machine learning, split-screen multitasking, picture-in-picture, and battery health checks. The one functional difference beyond the OS version is Focus Modes: the 15 Ultra supports them, the K90 Pro Max does not. Focus Modes allow users to filter notifications and limit accessible apps during work, sleep, or personal time — a productivity and wellbeing feature that some users rely on heavily, though others may never touch it.

Weighing both differences, the Redmi K90 Pro Max holds a slight OS edge by virtue of its newer Android 16 base. The 15 Ultra's Focus Modes support is a useful counter, but a more current OS version has broader implications for security and future compatibility. Neither advantage is dramatic, making this group largely a wash for most users — but for those who prioritize software freshness, the K90 Pro Max is the better-positioned device.

Raw capacity is where the Redmi K90 Pro Max makes its most dramatic statement in this comparison: a 7560 mAh battery against the Xiaomi 15 Ultra's already-generous 6000 mAh. That 1560 mAh gap — roughly 26% more energy storage — directly translates to extended screen-on time, less anxiety during long days away from a charger, and greater resilience as the battery ages over years of charge cycles. For heavy users, travellers, or anyone who simply dislikes charging frequently, this is a substantial real-world advantage.

Wired charging tells a similarly nuanced story. The K90 Pro Max supports 100W fast charging versus the 15 Ultra's 90W — a difference that, in practice, is minor. Where the two diverge more meaningfully is wireless charging: the 15 Ultra leads with 80W wireless compared to the K90 Pro Max's 50W, meaning the 15 Ultra can replenish wirelessly at a speed that rivals many phones' wired charging. For users who rely heavily on wireless pads, that 30W gap is genuinely useful. Reverse wireless charging favors the K90 Pro Max at 22.5W versus the 15 Ultra's 10W, making the K90 Pro Max a more capable power bank for topping up earbuds or smartwatches on the go.

Overall, the Redmi K90 Pro Max wins the battery category. Its larger capacity is the dominant factor, and its faster reverse wireless charging adds further utility. The 15 Ultra's superior wireless charging speed is a meaningful consolation for cord-free users, but for most people, a bigger battery that lasts longer will matter more day to day.

Both phones drop the 3.5mm headphone jack and offer stereo speakers — so for casual listening out loud, the experience is equivalent. The real divergence is entirely in wireless audio codec support, and it is one-sided: the Xiaomi 15 Ultra supports aptX, aptX HD, aptX Adaptive, aptX Lossless, and LDAC, while the Redmi K90 Pro Max supports none of them.

That distinction matters significantly for anyone using premium Bluetooth headphones or earbuds. Codecs like LDAC and aptX Lossless transmit substantially more audio data per second than standard SBC or AAC, preserving more of the original recording's detail and dynamics. Without these codecs, the K90 Pro Max is limited to compressed Bluetooth audio regardless of how high-end the connected headphones are — the bottleneck shifts entirely to the phone. The 15 Ultra, by contrast, can unlock the full potential of compatible high-fidelity wireless audio gear.

For this group, the 15 Ultra wins without contest. Users who listen via speakers or budget earbuds may never notice the gap, but for audiophiles or anyone invested in quality wireless headphones, the K90 Pro Max's complete absence of high-fidelity codec support is a meaningful limitation that the 15 Ultra sidesteps entirely.

Much of this category is a dead heat — both phones share 5G, dual SIM, USB 3.2 Type-C, NFC, Wi-Fi 7, identical cellular speeds, and the same core sensor suite. The differences that do exist, however, are all in the Xiaomi 15 Ultra's favor. It supports Wi-Fi 6E, which the Redmi K90 Pro Max lacks — adding access to the less congested 6GHz band for lower latency and more stable connections in dense environments like offices or apartment buildings. Its Bluetooth 6.0 is also a step ahead of the K90 Pro Max's Bluetooth 5.4, bringing improvements in connection precision and efficiency that benefit wireless peripherals and audio devices over time.

Two sensor-level omissions from the K90 Pro Max are worth flagging. The 15 Ultra includes a barometer, useful for accurate altitude readings and weather-aware apps — absent on the K90 Pro Max. More significantly, the 15 Ultra offers emergency SOS via satellite, a safety feature that allows distress signals to be sent even without cellular coverage. For hikers, travellers, or anyone venturing into remote areas, this is a potentially life-critical capability the K90 Pro Max simply does not have.

The 15 Ultra holds a clear advantage in connectivity and features. Wi-Fi 6E and the newer Bluetooth version represent future-facing improvements, but it is the satellite SOS capability that most meaningfully separates the two — a feature with no equivalent on the K90 Pro Max and one that speaks directly to the 15 Ultra's positioning as a more comprehensively equipped device.

The miscellaneous specs for the Xiaomi 15 Ultra and the Redmi K90 Pro Max are identical across every data point provided. Both include a video light, and neither features a sapphire glass display, a curved screen, or an e-paper display.

This group is a complete tie. The shared video light is a minor but practical feature for content creators shooting in low-light conditions, and the absence of sapphire glass, curved displays, and e-paper panels means neither phone targets niche use cases that those features would serve. There is nothing in this category to differentiate one device from the other.