iQOO 15 Ultra vs X300
Winner
Vivo iQOO 15 Ultra
The iQOO 15 Ultra wins this one, taking performance and software longevity decisively. Against the X300 it's also the sounder buy at $10.08 per month of safe use.
Value Score: iQOO 15 Ultra 79 · X300 73 — methodology
Who should pick which
Beyond the scores — our take on each phone and the buyer it actually suits.
iQOO's no-compromise gaming flagship pairs a Snapdragon 8 Elite Gen 5, a 7,400mAh battery and a 59-blade cooling fan with an unusually long 5-year OS / 7-year security promise that keeps it safe to use into 2033.
Pick it if
- ✓ Mobile gamers who keep phones for years
- ✓ Performance buyers who want the longest support window
Skip it if
- ✗ You need an official US warranty and full carrier bands
- ✗ You want a light, compact phone
A compact flagship with a genuinely long leash — 5 years of OS upgrades and 7 years of security patches make the X300 one of the longest-supported compact Android phones you can import today.
Pick it if
- ✓ compact-phone loyalists
- ✓ camera-focused buyers on a mid-flagship budget
Skip it if
- ✗ you need official US warranty and carrier support
- ✗ you require 1TB local storage
The lifespan decider
When specs are close, support length decides it — this is what each phone costs per month of safe use.
Category by category
Both displays are effectively the same class.
The iQOO 15 Ultra's Qualcomm Snapdragon 8 Elite Gen 5 is simply the faster chip.
The X300 has the stronger camera system — same lens count, higher-grade sensors.
Battery capacities are close enough not to decide this.
The iQOO 15 Ultra is supported until Feb 2033 — 3 months longer than the X300.
Overall value goes to the iQOO 15 Ultra at $10.08 per month of safe use.
Frequently asked
When does the iQOO 15 Ultra stop getting updates?
iQOO backs the iQOO 15 series with 5 major Android OS upgrades and 7 years of security patches, so a unit bought at the February 2026 launch is covered until roughly February 2033. That carries it from Android 16 all the way to Android 21 and is one of the longest support windows on any performance-focused Android phone, comfortably beating dedicated gaming handsets that typically stop at two or three years.
Is the iQOO 15 Ultra worth buying in 2026?
Yes, if you want maximum performance and plan to keep the phone. Even midway through 2026 you still have around six and a half years of security coverage ahead, the Snapdragon 8 Elite Gen 5 will not feel slow for years, and the 7,400mAh battery ages gracefully. The main caveats are the 227g weight and the import-only availability outside China.
How long will the Vivo X300 be supported?
Vivo has officially committed to 5 major Android OS updates and 7 years of security patches for the X300, dating from its October 2025 launch. That pushes its end-of-support date out to roughly October 2032, making it one of the longest-supported compact Android phones on the market.
Is the Vivo X300 available in the US?
No. Vivo does not sell the X300 through official US channels, so any US unit is a gray-market import without manufacturer warranty or guaranteed full-band 5G support on US carriers.
Full spec table
| Spec | iQOO 15 Ultra | X300 |
|---|---|---|
| Price (street) | $790 | $700 |
| Display | 6.85-inch AMOLED, 1440x3168, 144Hz, up to 8000 nits peak, Dolby Vision | 6.31-inch LTPO AMOLED, 1216p, 120Hz, up to 4500 nits peak brightness |
| Chipset | Qualcomm Snapdragon 8 Elite Gen 5 | MediaTek Dimensity 9500 |
| RAM | 16GB/24GB | 12GB/16GB |
| Storage | 256GB/512GB/1TB | 256GB/512GB |
| Battery | 7,400 mAh | 6,040 mAh |
| Charging | 100W wired, 40W wireless | 90W wired, 40W wireless |
| Rear cameras | 50MP main, 50MP telephoto 3x, 50MP ultra-wide | 200MP main, 50MP periscope 3x, 50MP ultra-wide |
| Dimensions | 163.7 x 76.8 x 8.7 mm | 150.57 x 71.92 x 7.95 mm |
| Weight | 227 g | 190 g |
| Water resistance | IP68/IP69 | IP68/IP69 |
| Supported until | Feb 2033 | Oct 2032 |
More comparisons
Scores and verdicts are computed from our verified database — see exactly how. Specs from manufacturer documentation; prices reflect major US retailers.