PhoneLifespan

ROG Phone 8 vs 15 Ultra

vs

Winner

Xiaomi 15 Ultra

Lifespan decides this one: the 15 Ultra is supported until Mar 2030 at $30.40 per month of safe use, while the ROG Phone 8 runs out in Jan 2029 ($27.42/month). On a which-lasts-longer question, that's not a tie — it's the whole answer.

Value Score: ROG Phone 8 60 · 15 Ultra 65 — methodology

The lifespan decider

When specs are close, support length decides it — this is what each phone costs per month of safe use.

Asus ROG Phone 8 $850
Buy with care$27.42/mo
2024◆ Buy-by Jan 20272029
Xiaomi 15 Ultra $1350
Safe to buy$30.40/mo
2025◆ Buy-by Mar 20282030

Category by category

Display
ROG Phone 8 8015 Ultra 100

The 15 Ultra's screen is the better one — 6.73-inch 2k (1440×3200) ltpo amoled, 1–120hz, up to 3200 nits peak.

Performance
ROG Phone 8 9215 Ultra 98

The 15 Ultra's Qualcomm Snapdragon 8 Elite (3nm) is simply the faster chip.

Camera
ROG Phone 8 7915 Ultra 96

The 15 Ultra has the stronger camera system (4 real rear lenses vs 3).

Battery
ROG Phone 8 9015 Ultra 88

Battery capacities are close enough not to decide this.

Software longevity
ROG Phone 8 3715 Ultra 53

The 15 Ultra is supported until Mar 2030 — 13 months longer than the ROG Phone 8.

Value
ROG Phone 8 6015 Ultra 65

Overall value goes to the 15 Ultra at $30.40 per month of safe use.

Full spec table
SpecROG Phone 815 Ultra
Price (street)$850$1350
Display6.78-inch LTPO AMOLED, 1080x2400, 165Hz6.73-inch 2K (1440×3200) LTPO AMOLED, 1–120Hz, up to 3200 nits peak
ChipsetQualcomm Snapdragon 8 Gen 3Qualcomm Snapdragon 8 Elite (3nm)
RAM12GB/16GB16GB
Storage256GB/512GB512GB/1TB
Battery5,500 mAh5,410 mAh
Charging65W wired, 15W wireless90W wired, 80W wireless
Rear cameras50MP main, 13MP ultra-wide, 32MP telephoto 3x50MP main, 50MP ultra-wide, 50MP telephoto (70mm floating), 200MP periscope telephoto
Dimensions163.8 × 76.8 × 8.9 mm161.3 × 75.3 × 9.35 mm
Weight225 g226 g
Water resistanceIP68IP68
Supported untilJan 2029Mar 2030
ROG Phone 8 full verdict →15 Ultra full verdict →Longevity master board →

Scores and verdicts are computed from our verified database — see exactly how. Specs from manufacturer documentation; prices reflect major US retailers.